differentia

[dif-uh-ren-shee-uh, -shuh] /ˌdɪf əˈrɛn ʃi ə, -ʃə/
noun, plural differentiae
[dif-uh-ren-shee-ee] /ˌdɪf əˈrɛn ʃiˌi/ (Show IPA)
1.
the character or attribute by which one species is distinguished from all others of the same genus.
2.
the character or basic factor by which one entity is distinguished from another.
Origin
1820-30; < Latin; see difference
British Dictionary definitions for differentia

differentia

/ˌdɪfəˈrɛnʃɪə/
noun (pl) -tiae (-ʃɪˌiː)
1.
(logic) a feature by which two subclasses of the same class of named objects can be distinguished Also called difference
Word Origin
C19: from Latin: diversity, difference