/ Dictionary / Index B bipinnaria: Meaning and Definition of Find definitions for: bi•pin•nar•i•a Pronunciation: (bī"pi-nâr'ē-u), [key] — pl. -nar•i•ae -nar•i•as. the free-swimming, bilaterally symmetrical larva of certain starfishes. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Biphetamine bipinnate Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language