Siddhaṃ (also Siddhāṃ) is an Indic script used in India from the 6th century to the 13th century. Also known in its later evolved form as Siddhamātṛkā, Siddham is a medieval Brahmic abugida, derived from the Gupta script and ancestral to the Nāgarī, Eastern Nagari, Tirhuta, Odia and Nepalese scripts. The Siddham script was widely used by Indian Buddhists and still remains in use by East Asian Buddhists, especially for writing mantras, seed syllables, and dharanis.
The word Siddhaṃ means "accomplished", "completed" or "perfected" in Sanskrit. The script received its name from the practice of writing Siddhaṃ, or Siddhaṃ astu (may there be perfection), at the head of documents. Other names for the script include bonji (Japanese: 梵字) "Brahma's characters" and "Sanskrit script" and Chinese: 悉曇文字; pinyin: Xītán wénzi "Siddhaṃ script".