Sinus

Sinus may refer to:

In anatomy, where a sinus is a sac or cavity in any organ or tissue:
 * Paranasal sinus, an air cavity in the cranial bones, especially those near the nose
 * Sinus (anatomy), description of the general term
 * Anal sinuses, the furrows which separate the columns in the rectum
 * Dural venous sinuses, venous channels found between layers of dura mater in the brain

In the heart: Other:
 * Sinus node, a structure in the superior part of the right atrium
 * Sinus rhythm, normal beating on an ECG
 * Coronary sinus, a vein collecting blood from the myocardium
 * Sinus venosus, a cavity in the heart of embryos
 * Sinus venarum, a part of the wall of the right atrium in adults, developed from the sinus venosus
 * Sinus (botany), a space or indentation, usually on a leaf
 * Sinus Asperitatis, an area on the Moon