sinus

(Lat.=a bay of the sea; a curve; a bend, a bosom.] *I. Ordinary Language : 1. A bay of the sea; a rece in the coast; an opening into the land. 2. An opening, a hollow, a sinuosity; a bend or curve. II. Technically : 3700 1. Anat .: A hollow. There are sinuses of the veins, a coronary sinus of the heart, a sinus of the vestibule, a frontal sinus , . Owen applies the term especially to a dilated vein or receptacle of blood. 2. Botany : A rece between two lobes of a lobed leaf. 3. Zool .: A bay in the pallial impre ion of a conchiferous mollusk, indicating that the animal had retractile siphons. 4. Surg.: A little elongated cavity in which pus is collected; an elongated absce with a small opening.