shear (v.)
Old English sceran, scieran (class IV strong verb; past tense scear, past participle scoren) "to cleave, hew, cut with a sharp instrument; cut (hair); shear (sheep)," from Proto-Germanic *sker- "to cut" (cognates: Old Norse and Old Frisian skera, Dutch scheren, German scheren "to shear"), from PIE *(s)ker- (1) "to cut, to scrape, to hack" (cognates: Sanskrit krnati "hurts, wounds, kills," krntati "cuts;" Hittite karsh- "to cut off;" Greek keirein "to cut, shear;" Latin curtus "short;" Lithuanian skiriu "to separate;" Old Irish scaraim "I separate;" Welsh ysgar "to separate," ysgyr "fragment").
shear (n.)
"act of clipping," 1610s, also as a unit of measure of the age of a sheep, from shear (v.). Scientific and mechanical sense "type of strain" is from 1850.