fission-fusion bomb

19 LETTERS · STARTS WITH F

fission-fusion bomb is a valid 19-letter word worth 29 points in Scrabble and 35 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

F4I1S1S1I1O1N1-0F4U1S1I1O1N1B3O1M3B3

4 + 1 + 1 + 1 + 1 + 1 + 1 + 0 + 4 + 1 + 1 + 1 + 1 + 1 + 0 + 3 + 1 + 3 + 3 =29 PTS

DOUBLE WORD → 58TRIPLE WORD → 87

MEANING

What does fission-fusion bomb mean?