While terms such as haecceity, quiddity, noumenon and hypokeimenon all evoke the essence of a thing, they each have subtle differences and refer to different aspects of the thing's essence.
Haecceity thus enabled Scotus to find a middle ground in the debate over universals between Nominalism and Realism.
Garfinkel ... used the word haecceity in his seminal Studies in Ethnomethodology (1967), to enhance the indexical inevitable character of any expression, behavior or situation. (wikipedia )