Synonym for piriform fossa ... A recess in the anterolateral wall of the nasopharynx on each side of the vestible of the larynx separated from it by the aryepiglottic folds. ... Synonym: recessus piriformis, piriform recess, piriform sinus. ... (05 Mar 2000) ... Found on http://www.encyclo.co.uk/local/20973