sinus
/ˈsaɪ.nəs/ noun
Forms sinuses
- noun (anatomy, zootomy) A pouch or cavity in a bone or other tissue, especially one in the bones of the face or skull connecting with the nasal cavities (the paranasal sinus).
- noun (anatomy) An irregular venous or lymphatic cavity, reservoir, or dilated vessel.
- noun (physiology, attributive) Relating to or denoting the sinoatrial node of the heart or its function of regulating the heartbeat.
- noun (pathology) An abnormal cavity or passage such as a fistula, leading from a deep-seated infection and discharging pus to the surface.
- noun (botany) A rounded notch or depression between two lobes or teeth in the margin of a leaf or petal.
- noun (geography) A bay of the sea; a recess in the shore.
- noun (trigonometry) Synonym of sine.
Synonyms
Etymology
Learned borrowing from Latin sinus (“a bent surface, curve, hollow”). Doublet of sine.
Webster’s 1913
Etymology [L., a bent surface, a curve, the folds or bosom of a garment, etc., a bay. Cf. Sine, n.]
Sources: Wiktionary · WordNet 3.0 · Webster’s 1913 — from the Wiktionary entry “sinus”, CC BY-SA 4.0. Details