From WordNet (r) 2.0 (August 2003) [wn]:
atomic
adj 1: of or relating to or comprising atoms; "atomic structure";
"atomic hydrogen"
2: (weapons) deriving destructive energy from the release of
atomic energy; "nuclear war"; "nuclear weapons"; "atomic
bombs" [syn: nuclear] [ant: conventional]
3: immeasurably small [syn: atomlike, minute]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Atomic \A*tom"ic\, Atomical \A*tom"ic*al\, a. [Cf. F. atomique.]
1. Of or pertaining to atoms.
[1913 Webster]
2. Extremely minute; tiny.
[1913 Webster]
Atomic bomb, see atom bomb in the vocabulary.
Atomic philosophy, or Doctrine of atoms, a system which,
assuming that atoms are endued with gravity and motion,
accounted thus for the origin and formation of all things.
This philosophy was first broached by Leucippus, was
developed by Democritus, and afterward improved by
Epicurus, and hence is sometimes denominated the Epicurean
philosophy.
Atomic theory, or the Doctrine of definite proportions
(Chem.), teaches that chemical combinations take place
between the supposed ultimate particles or atoms of
bodies, in some simple ratio, as of one to one, two to
three, or some other, always expressible in whole numbers.
Atomic weight (Chem.), the weight of the atom of an element
as compared with the weight of the atom of hydrogen, taken
as a standard.
[1913 Webster]
From The Free On-line Dictionary of Computing (19 Sep 2003) [foldoc]:
atomic
<jargon> (From Greek "atomos", indivisible) Indivisible;
cannot be split up.
For example, an instruction may be said to do several things
"atomically", i.e. all the things are done immediately, and
there is no chance of the instruction being half-completed or
of another being interspersed. Used especially to convey that
an operation cannot be interrupted.
An atomic data type has no internal structure visible to the
program. It can be represented by a flat domain (all
elements are equally defined). Machine integers and
Booleans are two examples.
An atomic database transaction is one which is guaranteed to
complete successfully or not at all. If an error prevents a
partially-performed transaction from proceeding to completion,
it must be "backed out" to prevent the database being left in
an inconsistent state.
[Jargon File]
(2000-04-03)
From Jargon File (4.4.4, 14 Aug 2003) [jargon]:
atomic
adj.
[from Gk. atomos, indivisible]
1. Indivisible; cannot be split up. For example, an instruction may
be said to do several things `atomically', i.e., all the things are
done immediately, and there is no chance of the instruction being
half-completed or of another being interspersed. Used esp. to convey
that an operation cannot be screwed up by interrupts. "This routine
locks the file and increments the file's semaphore atomically."
2. [primarily techspeak] Guaranteed to complete successfully or not
at all, usu. refers to database transactions. If an error prevents a
partially-performed transaction from proceeding to completion, it
must be "backed out", as the database must not be left in an
inconsistent state.
Computer usage, in either of the above senses, has none of the
connotations that `atomic' has in mainstream English (i.e. of
particles of matter, nuclear explosions etc.).