shareyoudaoicibaDictYouDict[share 词源字典]
share: Share ‘plough-blade’ [OE] and share ‘portion’ [14] are distinct words, but they are ultimately related. The former came from the Germanic base *skar-, *sker- ‘cut’, which also produced English score, shear, short, etc. Its German relative is schar ‘ploughshare’. Share ‘portion’ appears to be a survival of Old English scearu.

This is only recorded in the senses ‘groin’ and ‘tonsure’, but they share a meaning element (‘dividing’ in the case of the groin, the ‘forking’ of the body, and ‘cutting’ in the case of tonsure) that leads back to Germanic *skar-, *sker-, and suggests that share ‘portion’ denotes etymologically something ‘cut’ up or divided between people.

=> score, sharp, shear, shirt, short, skirt[share etymology, share origin, 英语词源]
share (n.1)youdaoicibaDictYouDict
"portion," Old English scearu "a cutting, shearing, tonsure; a part or division," related to sceran "to cut," from Proto-Germanic *skaro- (cognates: Old High German scara "troop, share of forced labor," German Schar "troop, band," properly "a part of an army," Old Norse skör "rim"), from PIE root *(s)ker- (1) "to cut" (see shear (v.)).

Meaning "part of the capital of a joint stock company" is first attested c. 1600. Share and share alike attested from 1560s. The same Old English noun in the sense "division" led to an obsolete noun share "fork ('division') of the body at the groin; pubic region" (late Old English and Middle English); hence share-bone "pubis" (early 15c.).
share (n.2)youdaoicibaDictYouDict
"iron blade of a plow," Old English scear, scær "plowshare," properly "that which cuts," from Proto-Germanic *skar- (cognates: Old Frisian skere, Middle Low German schar, Old High German scar, German Schar, Dutch ploegschaar, Middle High German pfluocschar), from PIE root *(s)ker- (1) "to cut" (see shear).
share (v.)youdaoicibaDictYouDict
1580s, "to apportion to someone as his share; to apportion out to others; to enjoy or suffer (something) with others," from share (n.1). Meaning "to divide one's own and give part to others" is recorded from 1590s. Meaning "confess one's sins openly" (1932, implied in sharing) is from "the language of Moral Rearmament" [OED]. Related: Shared; sharer; sharing.