Essentially contested concept refers to abstract terms or phrases that provide value judgements which can be contested. The term essentially contested concept was proposed to facilitate an understanding of the different interpretations of abstractions that have qualitative and evaluative notions—such as "art", "philanthropy", "power", and "social justice". The notion of essentially contested concept was proposed in 1956 by Walter Bryce Gallie.
Essentially contested concepts involve agreed on abstract concepts or phrases, but whose usage and interpretation is disputable by others (e.g. "social justice", "This picture is a work of art"). They are abstract concepts whose “proper use of which inevitably involves endless disputes about their proper uses on the part of their users", and these disputes "cannot be settled by appeal to empirical evidence, linguistic usage, or the canons of logic alone". Usually, essentially contested concepts are found in the social sciences where confusion arises due to experts using terminology inconsistently and often failing to specify the relationship between an abstract term and the meaning of that term.
For example, in historical studies, it has been observed that there are no particular standards for historical topics such as religion, art, science, democracy, and social justice, as these are by their nature 'essentially contested' fields that require diverse tools particular to each field beforehand in order to interpret topics from those subjects. When scholars talk about "religion", "art", "science", "democracy", etc, there is no one definition of such terms that is generally accepted, and thus they are essentially contested by default among scholars.