Meaning

noun a domesticated animal kept for companionship or amusement

noun a special loved one

noun a fit of petulance or sulkiness (especially at what is felt to be a slight)

originOriginally northern dialectal, from Scots pet (“an animal that has been tamed and is kept as a pet; a darling or favourite; a petted or spoiled child”), probably from Scottish Gaelic peata (“pet, tamed animal, spoiled child”), from Middle Irish petta, peta (“pet, lap-dog”), of uncertain origin, possibly from a pre-Indo-European substrate. Compare also peat (“pet, darling, woman”), which is likely…

Etymology from Wiktionary, CC BY-SA 3.0