/ Dictionary / Index C countersignature: Meaning and Definition of Find definitions for: coun•ter•sig•na•ture Pronunciation: (koun"tur-sig'nu-chur), [key] — n. a signature added by way of countersigning. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: countersignature (Thesaurus) countersign countersink Related Content Daily Word Quiz: lunar Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language