Type: Term Pronunciation: sil′vē-ŭs Definitions: 1. Le Böe, Franciscus (Fran瀀ois), Dutch physician, anatomist, and physiologist, 1614-1672. See: sylvian angle, sylvian aqueduct, sylvian fissure, sylvian line, sylvian point, sylvian valve, sylvian ventricle, fossa of Sylvius, vallecula sylvii