From Wiktionary, the free dictionary
(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.)
Likely derived from kesk-.
keset
- in the middle of, in the centre of, during, on
- Ta kukkus keset pidu kokku.
- She fainted in the middle of the party.
- Ta magas keset põrandat.
- He was sleeping on the floor.