The terms “equality” signify a qualitative relationship. ‘Equality’ signifies correspondence between a group of different objects, persons, processes or circumstances that have the same qualities in at least one respect, but not all respects, i.e., regarding one specific feature, with differences in other features. ‘Equality’ needs to thus be distinguished from ‘identity’ — this concept signifying that one and the same object corresponds to itself in all its features: an object that can be referred to through various individual terms, proper names, or descriptions. For the same reason, it needs to be distinguished from ‘similarity’ — the concept of merely approximate correspondence . Thus, to say e.g. that men are equal is not to say that they are identical. Equality implies similarity rather than ‘sameness.’
(Stanford Encyclopedia of Philosophy)