/ Dictionary / Index B base period: Meaning and Definition of Find definitions for: base' pe"riod Pronunciation: [key] a period of time used as a standard of comparison in measuring changes in prices, taxes, income, etc., at other periods of time. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. base pay baseplate Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language