/ Dictionary / Index R reckoner: Meaning and Definition of Find definitions for: reck•on•er Pronunciation: (rek'u-nur), [key] — n. a person who reckons. Also calleda collection of mathematical and other tables for ready calculation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: reckoner (Thesaurus) reckon reckoning Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language