atomic

UK: /əˈtɒmɪk/ US: /əˈtɑmɪk/ ,(ə tom′ik)

WordReference Random House Learner's Dictionary of American English © 2026

a•tom•ic /əˈtɑmɪk/   adj. [before a noun]

1. Physics of, relating to, resulting from, or using atoms, atomic energy, or atomic bombs.
2. Chemistry existing as free, uncombined atoms:
   atomic hydrogen.

a•tom•i•cal•ly, adv. See -tom-.

WordReference Random House Unabridged Dictionary of American English © 2026

a•tom•ic  (ə tom′ik), adj. 

1. Physics of, pertaining to, resulting from, or using atoms, atomic energy, or atomic bombs:
   an atomic explosion.
2. Physics propelled or driven by atomic energy:
   an atomic submarine.
3. Chemistry existing as free, uncombined atoms.
4. extremely minute.

Also, a•tom′i•cal. 

• atom + -ic 1670–80

a•tom′i•cal•ly, adv. 

Collins Concise English Dictionary © HarperCollins Publishers::

atomic / əˈtɒmɪk/ adjective

1. of, using, or characterized by atomic bombs or atomic energy: atomic warfare
2. of, related to, or comprising atoms: atomic hydrogen

aˈtomically adverb