In the following prefixes, a final vowel is normally dropped before a root that begins with a vowel, with the exceptions of bi-, which is extended to bis- before a vowel; among the other monosyllables, du-, di-, dvi-, and tri-, never vary.
The same suffix may be used with more than one category of number, as for example the orginary numbers secondary and tertiary and the distributive numbers binary and ternary.
Many of the items in the following tables are not in general use, but may rather be regarded as coinages by individuals. In scientific contexts, either scientific notation or SI prefixes are used to express very large or very small numbers, and not unwieldy prefixes.
Number prefixes in EnglishNumerical prefixes are not restricted to denoting integers. Some of the SI prefixes denote negative powers of 10, i.e. division by a multiple of 10 rather than multiplication by it. Several common-use numerical prefixes denote vulgar fractions.
Words containing non-technical numerical prefixes are usually not hyphenated. This is not an absolute rule, however, and there are exceptions (for example: quarter-deck occurs in addition to quarterdeck). There are no exceptions for words comprising technical numerical prefixes, though. Systematic names and words comprising SI prefixes and binary prefixes are not hyphenated, by definition.
Nonetheless, for clarity, dictionaries list numerical prefixes in hyphenated form, to distinguish the prefixes from words with the same spellings (such as duo- and duo).
Several technical numerical prefixes are not derived from words for numbers. (mega- is not derived from a number word, for example.) Similarly, some are only derived from words for numbers inasmuch as they are word play. (Peta- is word play on penta-, for example. See its etymology for details.) The metric prefixes peta, exa, zetta, yotta, ronna, and quetta are based on the Ancient Greek or Ancient Latin numbers from 5 to 10, referring to the fifth through tenth powers of 1000. The initial letter h has been removed from some of these stems and the initial letters z, y, r, and q have been added, ascending in reverse alphabetical order, to avoid confusion with other metric prefixes.
The root language of a numerical prefix need not be related to the root language of the word that it prefixes. Some words comprising numerical prefixes are hybrid words.
In certain classes of systematic names, there are a few other exceptions to the rule of using Greek-derived numerical prefixes. The IUPAC nomenclature of organic chemistry, for example, uses the numerical prefixes derived from Greek, except for the prefix for 9 (as mentioned) and the prefixes from 1 to 4 (meth-, eth-, prop-, and but-), which are not derived from words for numbers. These prefixes were invented by the IUPAC, deriving them from the pre-existing names for several compounds that it was intended to preserve in the new system: methane (via methyl, which is in turn from the Greek word for wine), ethane (from ethyl coined by Justus von Liebig in 1834), propane (from propionic, which is in turn from pro- and the Greek word for fat), and butane (from butyl, which is in turn from butyric, which is in turn from the Latin word for butter).
These months' prefixes originated in a conjectured, pre-historical Roman 10 month calendar. See Roman Calendar. /wiki/Roman_Calendar
See Mendeleev's predicted elements for the most common use of Sanskrit numerical prefixes. /wiki/Mendeleev%27s_predicted_elements
The numbering adjectives in Greek are inflectional for grammatical gender (i.e. there is monos [masculine for single/alone], mone [feminine for single/alone] and monon [neuter for single/alone]), grammatical case (i.e. nominative, genitive, etc.) and grammatical number (singular/plural). The prefixes are produced from the default grammatical type (masculine/nominative/singular). /wiki/Grammatical_gender
See Mendeleev's predicted elements for the most common use of Sanskrit numerical prefixes. /wiki/Mendeleev%27s_predicted_elements
uncia. Charlton T. Lewis and Charles Short. A Latin Dictionary on Perseus Project. http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0059:entry=uncia
Demi- is French, from Latin dimidium.
e.g. hemisphere /wiki/Sphere#Hemisphere
e.g. universe, unilateral /wiki/Universe
sol (sōlus) is more appropriately a Latin root for "only", "oneself".
e.g. solo, soliloquy https://en.wiktionary.org/wiki/solo
sim- (sin-) is found in the words simplex, simple.
e.g. monogamy /wiki/Monogamy
e.g. holocaust, holography /wiki/Holocaust
The Greek prefix for 'one' is normally mono- 'alone'. Hen- 'one' is only used in compound numbers (hendeka- 11) and a few words like henad (= monad). Haplo- 'single' is found is a few technical words such as haploid. /wiki/Haploid
The Greek prefix for 'one' is normally mono- 'alone'. Hen- 'one' is only used in compound numbers (hendeka- 11) and a few words like henad (= monad). Haplo- 'single' is found is a few technical words such as haploid. /wiki/Haploid
πρῶτος. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=prw=tos
e.g. proton, protozoa /wiki/Proton
Monier-Williams, Monier (1899). "एक-". A Sanskrit-English Dictionary: Etymologically and Philologically Arranged with Special Reference to Cognate Indo-European Languages. Oxford: Clarendon Press. OCLC 685239912. /wiki/Monier_Monier-Williams
e.g. quasquicentennial https://en.wiktionary.org/wiki/quasquicentennial
e.g. sesquicentennial, sesquipedalian https://en.wiktionary.org/wiki/sesquicentennial
e.g. bireme, bilingual, bipolar, bipartisan /wiki/Bireme
δύο https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=du/o
δίς https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=di/s
δεύτερος https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=deu/teros
e.g. Deuteron/ium, Deuteronomy /wiki/Deuterium
Monier-Williams, Monier (1899). "द्वि-". A Sanskrit-English Dictionary: Etymologically and Philologically Arranged with Special Reference to Cognate Indo-European Languages. Oxford: Clarendon Press. OCLC 685239912. /wiki/Monier_Monier-Williams
e.g. sesterterpene https://en.wiktionary.org/wiki/sesterterpene
e.g. semiquincentennial https://en.wiktionary.org/wiki/semiquincentennial
e.g. trireme /wiki/Trireme
e.g. triathlon, Tripolis /wiki/Triathlon
τρίς https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=tri/s
τρίτος https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=tri/tos
e.g. Triton/ium /wiki/Tritium
Monier-Williams, Monier (1899). "त्रि-". A Sanskrit-English Dictionary: Etymologically and Philologically Arranged with Special Reference to Cognate Indo-European Languages. Oxford: Clarendon Press. OCLC 685239912. /wiki/Monier_Monier-Williams
The forms related to quattuor "four", like the previous three integers, are irregular in Latin and other Indo-European languages, and the details, while presumably a form of assimilation, are unclear.[11] In particular, quadri- has the alternate form quadru- before p in some Latin words, such as quadruple. /wiki/Assimilation_(linguistics)
"quăter". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D5%3Aentry%3Dquater
"quăterni". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D5%3Aentry%3Dquaterni
"quartus". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dquartus
e.g. tetrahedron /wiki/Tetrahedron
Monier-Williams, Monier (1899). "चतुर्-". A Sanskrit-English Dictionary: Etymologically and Philologically Arranged with Special Reference to Cognate Indo-European Languages. Oxford: Clarendon Press. OCLC 685239912. /wiki/Monier_Monier-Williams
"quinque". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D7%3Aentry%3Dquinque1
"quīni". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D7%3Aentry%3Dquini
"quintus". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dquintus1
e.g. pentahedron /wiki/Pentahedron
πέμπτος https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=pe/mptos
Monier-Williams, Monier (1899). "पञ्च-". A Sanskrit-English Dictionary: Etymologically and Philologically Arranged with Special Reference to Cognate Indo-European Languages. Oxford: Clarendon Press. OCLC 685239912. /wiki/Monier_Monier-Williams
Sometimes Greek hexa- is used in Latin compounds, such as hexadecimal, due to taboo avoidance with the English word sex. /wiki/Hexadecimal
"sēni". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dseni
"sextus". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dsextus1
Liddell, Henry George; Scott, Robert. "ἕξ". A Greek-English Lexicon. Archived from the original on 23 December 2021. Retrieved 24 February 2022 – via perseus.tufts.edu. https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=e(/c
e.g. hexahedron /wiki/Hexahedron
ἕκτος in Liddell, Henry George; Scott, Robert (1889) An Intermediate Greek–English Lexicon, Oxford. Clarendon Press. In the Perseus Digital Library, Tufts University. https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0058:entry=e(/ktos
Monier-Williams, Monier (1899). "षट्-". A Sanskrit-English Dictionary: Etymologically and Philologically Arranged with Special Reference to Cognate Indo-European Languages. Oxford: Clarendon Press. OCLC 685239912. /wiki/Monier_Monier-Williams
e.g. September
"septēni". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dsepteni
ἑπτά https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=e(pta/
e.g. heptathlon /wiki/Heptathlon
e.g. hebdomas https://en.wiktionary.org/wiki/hebdomas
Monier-Williams, Monier (1899). "सप्त-". A Sanskrit-English Dictionary: Etymologically and Philologically Arranged with Special Reference to Cognate Indo-European Languages. Oxford: Clarendon Press. OCLC 685239912. /wiki/Monier_Monier-Williams
e.g. October
"octōni". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Doctoni
"octāvus". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Doctavus
e.g. octopus /wiki/Octopus
e.g. octahedron /wiki/Octahedron
e.g. November
ἐννέα https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=e)nne/a
ἔνατος https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=e)/natos
e.g. December
"dēni". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Ddeni
"dĕcĭmus". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Ddecimus1
δέκα https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=de/ka
e.g. decathlon, decahedron, decagon /wiki/Decathlon
δέκατος https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=de/katos
"undēni". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DU%3Aentry+group%3D4%3Aentry%3Dundeni
"undĕcĭmus". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dundecimus
ἕνδεκα https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=e(/ndeka
ἑνδέκατος https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=e(nde/katos
e.g. duodenum /wiki/Duodenum
δώδεκα https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=dw/deka
e.g. dodecahedron /wiki/Dodecahedron
δωδέκατος https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=dwde/katos
e.g. triskaidekaphobia /wiki/Triskaidekaphobia
e.g. tetradecahedron/decatetrahedron /wiki/Tetradecahedron
"quindĕcim". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D7%3Aentry%3Dquindecim
"quindēni". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D7%3Aentry%3Dquindeni
"quindĕcĭmus". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D7%3Aentry%3Dquindecimus
"sēdĕcim". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dsedecim
For Latinate 21, 22, etc., the pattern for the teens is followed: unvigint-, duovigint-, etc. For higher numbers, the reverse order may be found: 36 is trigintisex-. For Greek, the word kai ("and") is used: icosikaihena-, icosikaidi-, pentacontakaipenta-, etc. In these and in the tens, the kai is frequently omitted, though not in triskaidekaphobia. (The inconsistency of triskaidekaphobia with the table above is explained by the fact that the Greek letter kappa can be transliterated either "c" or "k".) In chemical nomenclature, 11 is generally mixed Latin-Greek undeca-, and the 20s are based on -cos-, for example tricos- for 23. /wiki/Triskaidekaphobia
e.g. (e)icosahedron /wiki/Icosahedron
e.g. docosa-hexaenoic acid (a pejoration of dyoicosa-hexanoic) /wiki/Docosahexaenoic_acid
e.g. (e)icositetragon /wiki/Icositetragon
e.g. eicosapenta-enoic acid /wiki/Eicosapentaenoic_acid
e.g. triacontahedron /wiki/Triacontahedron
"quinquāginta". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D7%3Aentry%3Dquinquaginta
"quinquāgēni". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D7%3Aentry%3Dquinquageni
"quinquāgēsĭmus". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D7%3Aentry%3Dquinquagesimus
e.g. penteconter /wiki/Penteconter
e.g. pentecost /wiki/Pentecost
e.g. Septuagint /wiki/Septuagint
Lewis, Charlton T.; Short, Charles. "S". septĭfārĭam, septŭāgēsimus. A Latin Dictionary. Archived from the original on 26 July 2020. Retrieved 26 February 2019 – via perseus.tufts.edu. https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0059:alphabetic+letter=S:entry+group=34:entry=septuagesimus
e.g. sesquicentennial https://en.wiktionary.org/wiki/sesquicentennial
e.g. semiquincentennial https://en.wiktionary.org/wiki/semiquincentennial
"quingenti". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D7%3Aentry%3Dquingenti
"quincenti". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D7%3Aentry%3Dquincenti
"quingēni". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D7%3Aentry%3Dquingeni
"quingentēsĭmus". Archived from the original on 14 October 2012. Retrieved 14 May 2011. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aalphabetic+letter%3DQ%3Aentry+group%3D7%3Aentry%3Dquingentesimus
ἐννακόσιοι https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=e)nnako/sioi
ἐνακοσιοστός https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=e)nakosiosto/s
χίλιοι https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=xi/lioi
χιλιοστός https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=xiliosto/s
δισχίλιοι https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=disxi/lioi
τρισχίλιοι https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=trisxi/lioi
τρισχιλιοστός https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=trisxiliosto/s
πεντακισχίλιοι https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=pentakisxi/lioi
μυρίος https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=muri/os
e.g. myriapoda /wiki/Myriapoda
μυριαστός https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=muriasto/s
ὀκτακισμύριοι https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=o)ktakismu/rioi
e.g. pauciparous https://en.wiktionary.org/wiki/pauciparous
e.g. oligopoly, oligarchy, oligomer, oligonucleotide, oligopeptide, oligosaccharide /wiki/Oligopoly
e.g. multilingual, multiple, pluripotent, pluricentric /wiki/Multilingual
e.g. polyhedra, polygamy, polypod, polyglot, polymath, polymer /wiki/Polyhedra
e.g. plethora https://en.wiktionary.org/wiki/plethora
The forms related to quattuor "four", like the previous three integers, are irregular in Latin and other Indo-European languages, and the details, while presumably a form of assimilation, are unclear.[11] In particular, quadri- has the alternate form quadru- before p in some Latin words, such as quadruple. /wiki/Assimilation_(linguistics)
In organic chemistry, most prefixes are Greek but the prefixes for 9 and 11 are Latin.