Sinus may refer to:
History a sac in front of body worn into a toga, in the typical style of wearing it
Anatomy Sinus (anatomy), a sac or cavity in any organ or tissue Paranasal sinuses, air cavities in the cranial bones, especially those near the nose, including: Maxillary sinus, the largest of the paranasal sinuses, under the eyes, in the maxillary bones Frontal sinus, superior to the eyes, in the frontal bone, which forms the hard part of the forehead Ethmoid sinus, formed from several discrete air cells within the ethmoid bone between the eyes and under the nose Sphenoidal sinus, in the sphenoid bone at the center of the skull base under the pituitary gland 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 Sinus (botany), a space or indentation, usually on a leaf
Heart Sinoatrial node (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 heart 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
Other uses Sinus (Chalcidice), a town of ancient Chalcidice, Greece Sinus, gulf or bay in Latin, used in numerous toponyms in ancient writing (e.g., Sinus Magnus, Sinus Flanaticus, etc.) Sine, a trigonometric math function (Latin sinus) Sinus, an EP by The Nope (Moka Only and Psy), 2014
See also Sinus Medii, a small lunar mare Sinus Successus, a lunar feature Sines, a municipality in Alentejo, Portugal (Latin Sinus) Sinusitis, a common ailment resulting in the inflammation of the paranasal sinuses