/ Dictionary / Index B billet-doux: Meaning and Definition of Find definitions for: bil•let-doux Pronunciation: (bil'ā-d', bil'ē- Fr. bē-yā-d'), [key] — pl. bil•lets-doux a love letter. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: billet-doux (Thesaurus) billet billethead 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