herd (n.) Look up herd at Dictionary.com
Old English heord "herd, flock," from Proto-Germanic *herdo- (cognates: Old Norse hjorð, Old High German herta, German Herde, Gothic hairda "herd"), from PIE *kerdh- "a row, group, herd" (cognates: Sanskrit śárdhah "herd, troop," Old Church Slavonic čreda "herd," Greek korthys "heap," Lithuanian kerdžius "shepherd"). Herd instinct in psychology is first recorded 1908.
herd (v.) Look up herd at Dictionary.com
mid-13c., “to watch over or herd (livestock);” of animals, “to gather in a herd, to form a flock,” late 14c., from herd (n.). Related: Herded; herding.