I. yak 1 /jæk/ BrE AmE noun [countable]
[ Date: 1700-1800 ; Language: Tibetan ; Origin: gyak ]
an animal of central Asia that looks like a cow with long hair
II. yak 2 BrE AmE verb ( past tense and past participle yakked , present participle yakking ) [intransitive]
[ Date: 1900-2000 ; Origin: From the sound of continuous talk ]
informal to talk continuously about things that are not very serious, in a way that is annoying