time bomb

WordReference Random House Unabridged Dictionary of American English © 2026

time′ bomb′, 

1. a bomb constructed so as to explode at a certain time.
2. a situation, condition, etc., resembling such a bomb in having disastrous consequences in the future.
• 1890–95

Collins Concise English Dictionary © HarperCollins Publishers::

time bomb, timebomb / ˈtaɪmˌbɒm/ noun

1. a bomb containing a timing mechanism that determines the time at which it will detonate