| Sinus 1. (n.) An opening or cavity, specifically that connecting to the nasal cavity. 2. (n.) An opening; a hollow; a bending. 3. (n.) A bay of the sea; a recess in the shore. 4. (n.) A cavity; a depression. 5. (n.) A cavity in a bone or other part, either closed or with a narrow opening. 6. (n.) A dilated vessel or canal. 7. (n.) A narrow, elongated cavity, in which pus is collected; an elongated abscess with only a small orifice. 8. (n.) A depression between adjoining lobes. Thesaurus Entries alveolation, alveolus, antrum, arc, armpit, basin, bow, bowl, catacaustic, catenary, caustic, cavity, circle, concave, concavity, conchoid, crater, crook, crypt, cup, curl, curve, depression, diacaustic, dip, ellipse, festoon, fold, follicle, funnel chest, hole, hollow, hollow shell, hook, hyperbola, lacuna, lituus, parabola, pit, pocket, punch bowl, scoop, shell, sink, socket, tracery, trough, vug |