/ Dictionary / Index B booster seat: Meaning and Definition of Find definitions for: boost'er seat" Pronunciation: [key] a padded seat that can be placed on a chair seat, for seating a child at the proper height, as at a table or in a barber chair. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. boosterism boost-start Related Content Daily Word Quiz: frugal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language