The Collaborative International Dictionary of English v.0.48:

Bullace \Bul"lace\, n. [OE. bolas, bolace, OF. beloce; of Celtic
   origin; cf. Arm. bolos, polos, Gael. bulaistear.] (Bot.)
      (a) A small European plum (Prunus communis, var.
          insitita). See Plum.
      (b) The bully tree.
          [1913 Webster]