Yours, Etc.: Origins and Uses of 8 Sign-Offs
1816, from Medieval Latin differentiatus, past participle of differentiare, from Latin differentia (see difference).
Originally a mathematical term; transitive and non-technical sense of "discriminate between" is from 1876. Earlier, difference had been used as a verb in this sense. Related: Differentiated; differentiating; differentiation.
undifferentiated un·dif·fer·en·ti·at·ed (ŭn'dĭf-ə-rěn'shē-ā'tĭd)
Having no special structure or function; primitive; embryonic.