From Longman Dictionary of Contemporary Englishpeckpeck1 /pek/ verb 1 
[intransitive, transitive]HBB if a bird pecks something or pecks at something, it makes quick repeated movements with its beak to try to eat part of it, make a hole in it etcpeck at birds pecking at breadcrumbs on the pavement2 → peck somebody on the cheek/forehead etc → peck at something→ See Verb table
[intransitive, transitive]HBB if a bird pecks something or pecks at something, it makes quick repeated movements with its beak to try to eat part of it, make a hole in it etcpeck at birds pecking at breadcrumbs on the pavement2 → peck somebody on the cheek/forehead etc → peck at something→ See Verb tableExamples from the Corpus
peck• The woodpecker's long beak is specially designed for pecking.• A surprising chaff inch flew down to peck at our crumbs.• Hens pecked at the corn scattered on the ground.• He himself had been but little pecked at.• You peck away at your computer, but it is hard for you to get motivated.• We were woken at the crack of dawn by the pitter patter of seagulls as they pecked for their breakfast.• There was a red mark where the pigeon had pecked her hand.• This means that the rider can help his horse should he peck on landing or hesitate into a fence.• Beneath that principled veneer students were hammering out the usual adolescent pecking order.• Males compete with one another for places in a pecking order.• She pecked our hands for food and glared at us with her red eyes.peck at• Chickens peck at the corn on the ground.peckpeck2 noun [countable] 1 KISSa quick light kiss He gave her a quick peck on the cheek.2 HBBan action in which a bird pecks someone or something with its beakExamples from the Corpus
peck• Dottie Newland is a peck of fun.• He gave her a really big kiss. Not just a peck on the cheek.• Just a peck on the cheek.• The wife and kids took a peck at the visitor.• Take your child along and let him cat his peck of dirt.• I take the same two-hour bus and tram ride for the same old peck on the cheek.• One peck on the head will kill them.• It takes several pecks for the chick to make a hole in the eggshell.• Not bad, as the consequence of but a single peck!Origin peck1 (1300-1400) Probably from pick peck2 (1600-1700) → PECK1 