- 1[transitive, intransitive] to cover something, or to become covered, with a thin white layer of ice frost something (over/up) The mirror was frosted up. frost (over/up) The windows had frosted over.
- 2 [transitive] frost something to cover a cake, etc with frosting
NAmE//frɔst//Verb Forms present simple I / you / we / they frost
he / she / it frosts
past simple frosted
-ing form frosting