Choana: (Plural: choanae) The passageway from the back of one side of the nose to the throat. There are two choanae, one on either side of the nose. The choanae must be open to permit breathing through the nose. The noun choana is less used than the adjective choanal, as in choanal atresia (blockage of the choanal passage) and choanal stenosis (narrowing of the choanal passage). From the Greek choane (a funnel).