partyoudaoicibaDictYouDict[part 词源字典]
part: [13] Latin pars, a possible relative of parāre ‘make ready’ (source of English prepare), had a wide range of meanings – ‘piece’, ‘side’, ‘share’, etc – many of them shared by its English descendant part. The word was originally acquired in the late Old English period, but does not seem to have survived, and as we now have it was reborrowed via Old French part in the 13th century.

Other English descendants of pars include parcel, parse [16] (based on the notion of ‘parts’ of speech), partake [16] (a backformation from partaker [14], itself created from part and taker), partial [15], participate, participle, particle, particular, partisan, partition, partner, and party.
=> parcel, parse, partial, particle, partisan, partner, party[part etymology, part origin, 英语词源]
part (n.)youdaoicibaDictYouDict
mid-13c., "division, portion of a whole," from Old French part "share, portion; character; power, dominion; side, way, path," from Latin partem (nominative pars) "a part, piece, a share, a division; a party or faction; a part of the body; a fraction; a function, office," related to portio "share, portion," from PIE root *pere- (2) "to assign, grant, allot" (reciprocally, "to get in return;" cognates: Greek peprotai "it has been granted," Sanskrit purtam "reward," Hittite parshiya- "fraction, part").

It has replaced native deal (n.) in most senses. Theatrical sense (late 15c.) is from an actor's "share" in a performance (The Latin plural partis was used in the same sense). Meaning "the parting of the hair" is 1890, American English.

As an adjective from 1590s. Late Old English part "part of speech" did not survive and the modern word is considered a separate borrowing. Phrase for the most part is from late 14c. To take part "participate" is from late 14c.
part (v.)youdaoicibaDictYouDict
c. 1200, "to divide into parts; separate oneself," from Old French partir "to divide, separate" (10c.), from Latin partire, partere "to share, part, distribute, divide," from pars (see part (n.)).

Sense of "to separate (someone from someone else)" is from early 14c.; that of "to take leave" is from early 15c. Meaning "to separate the hair" is attested from 1610s. Related: Parted; parting. To part with "surrender" is from c. 1300.