(OED adj. pl.) “pastoral, relating to country life or the affairs and occupations of a shepherd,” 1610s, earlier bucolical (1520s), from Latin bucolicus, from Greek boukolikos “pastoral, rustic,” from boukolos “cowherd, herdsman,” from bous “cow” (from PIE root *gwou- “ox, bull, cow”) + -kolos “tending,” related to Latin colere “to till (the ground), cultivate, dwell, inhabit” (from PIE root *kwel- (1) “revolve, move round; sojourn, dwell”). Middle Irish búachaill, Welsh bugail “shepherd” are Celtic words formed from the same root material as Greek boukolos.