cep

1. flail
   Nekada se žito mlatilo cepom. — Grain used to be threshed with a flail.
2. (in gardening) scion; graft
   Deda je na staru jabuku stavio novi cep. — Grandpa grafted a new scion onto the old apple tree.

For "graft, scion" the word kalem is much more common.