Haecceity (; from the
Latin haecceitas, which translates as "thisness") is a term from
medieval scholastic philosophy, first coined by
Duns Scotus, which denotes the discrete qualities, properties or characteristics of a thing which make it a
particular thing. Haecceity is a person or object's "thisness", the individualising difference between the concept 'a man' and the concept 'Socrates' (a specific person). Haecceity is a literal translation of the equivalent term in
Aristotle's
Greek to ti esti (τὸ τί ἐστι) or "the what (it) is."