One of exactly two siblings produced from the splitting of a single zygote.

(philosophy) The principle that, if two objects are indistinguishable from one another with respect to all of their properties, then they are identical.

(philosophy) The principle that if two objects are absolutely identical then they must be indistinguishable from one another with respect to all of their properties.

plural of identity crisis

(mathematics, of a function) Being equal to the zero function and not merely zero at a particular point in its domain.

(US, Canada, law) A government regulation establishing the criteria which must be met before a product may be labeled as being a certain food.

plural of identity politician

(mathematics) Given a binary operation × defined on a set S which also has additive operation + and additive identity 0, the property that a × (b×c) + b × (c×a) + c × (a×b) = 0 for all a, b, c in S.

plural of Jacobi identity

(sociology) An identity or feeling of belonging to a group.