Definition of letter-bomb:
(n) :
A symbol in an alphabet.
(n) :
A written or printed communication, generally longer and more formal than a note.
(n) :
The literal meaning of something, as distinguished from its intended and remoter meaning (the spirit).
(n) :
(in the plural) Literature.
(n) :
(US, uncountable) A size of paper, 8½ in × 11 in (215.9 mm × 279.4 mm).
(n) :
(Canada, uncountable) A size of paper, 215 mm × 280 mm.