1530s, "nominate to a church office," from Medieval Latin postulatus, past participle of postulare "to ask, demand; claim; require," probably formed from past participle of Latin poscere "ask urgently, demand," from *posk-to-, Italic inchoative of PIE root *prek- "to ask questions" (cf. Sanskrit prcchati, Avestan peresaiti "interrogates," Old High German forskon, German forschen "to search, inquire"). Use in logic dates from 1640s, borrowed from Medieval Latin.
1580s, "a request, demand," from Latin postulatum "demand, request," properly "that which is requested," noun use of neuter past participle of postulare (see postulate (v.)). The sense in logic of "self-evident proposition" is from 1640s. The earlier noun in English was postulation (c.1400).
postulate pos·tu·late (pŏs'chə-lāt')
v. pos·tu·lat·ed, pos·tu·lat·ing, pos·tu·lates
To assume or assert the truth or necessity of, especially as a basis of an argument. n.
An unproved assertion or assumption, especially a statement offered as the basis of a theory.
A statement accepted as true for the purposes of argument or scientific investigation; also, a basic principle. (See axiom.)