the GNU version of the Collaborative International Dictionary of English
n. A figure of speech in which the speaker breaks off suddenly, as if unwilling or unable to state what was in his mind.”
The Century Dictionary and Cyclopedia
n. In rhetoric, sudden reticence; the suppression by a speaker or writer of something which he seemed to be about to say; the sudden termination of a discourse before it is really finished.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. breaking off in the middle of a sentence (as by writers of realistic conversations)
Word Usage
"There is no figurative language here; but there is the figure of aposiopesis, which (since it's just an artful breaking off of a sentence) is never figurative (in the sense we usually mean)."