/ Dictionary / Index E expansion bolt: Meaning and Definition of Find definitions for: expan'sion bolt" Pronunciation: [key] — Building Trades. Building Trades. a bolt inserted into a hole drilled in masonry and mechanically expanded to serve as an anchor for shelves, timbers, etc. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. expansion bit expansion card Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language