/ Dictionary / Index L labellum: Meaning and Definition of Find definitions for: la•bel•lum Pronunciation: (lu-bel'um), [key] — pl. -bel•la the petal of an orchid that differs more or less markedly from the other petals, often forming the most conspicuous part; the lip. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. La Belle Dame Sans Merci* labetalol Related Content Daily Word Quiz: slough Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language