Sinus

sī′nus, n. a bending: a fold: an opening: a bay of the sea: a rece on the shore: ( an at. ) a cavity or hollow of bone or other ti ue, one of the air-cavities contained in the interior of certain bones: a channel for transmitting venous blood: a narrow opening leading to an absce , .— n. Sī′nusoid , the curve of sines in which the absci es are proportional to an angle, and the ordinates to its sine.— adj. Sinusoi′dal .— adv. Sinusoi′dally . [L. sinus , a curve.]