WordNet sense 1 (a prominent aspect of something):

feature

WordNet sense 2 (any measurable property of a device measured under closely specified conditions):

device characteristic

WordNet sense 3 (characteristic of one only; distinctive or special):

peculiar

WordNet sense 4 (of a feature that helps to distinguish a person or thing):

distinctive, typical

WordNet sense 5 (characteristic or indicative of e.g. a disease):

diagnostic