postyoudaoicibaDictYouDict[post 词源字典]
post: Including the prefix post-, English has four different words post. The oldest, ‘long upright piece of wood, metal, etc’ [OE], was borrowed from Latin postis. From it was derived the verb post ‘fix to a post’, which in turn produced poster [19], denoting a placard that can be ‘posted’ up. Post ‘mail’ [16] comes via French poste and Italian posta from Vulgar Latin *posta, a contracted version of posita, the feminine form of the past participle of Latin pōnere ‘put, place’ (source of English position).

The notion underlying the sense ‘mail’ is of riders ‘placed’ or stationed at intervals along a road so as to carry letters at speed by a relay system. Post ‘job’ [16] reached English via a very similar route, this time from the neuter form of the Latin past participle, positum. This became *postum in Vulgar Latin, which produced Italian posto, French poste, and English post.

Here again the word’s original meaning, ‘position where a soldier is placed’, reflects that of its Latin source pōnere. The prefix post- comes from the Latin preposition post ‘after’. It occurs in a number of English words that go back to Latin ancestors (including posterior [16], posthumous, postpone [16], postscript [16], and the more heavily disguised preposterous), as well as being widely used to create new coinages (such as postgraduate [19] and postwar [20]).
=> position[post etymology, post origin, 英语词源]
post-graduate (adj.)youdaoicibaDictYouDict
also postgraduate, 1858, originally American English, from post- + graduate (adj.). As a noun, attested from 1890. Abbreviation post-grad is recorded from 1950.