sinus

/ˈsaɪnəs/

/ˈsaɪnəs/

Other forms: sinuses

A sinus infection is when the sinuses near your nose get clogged and your face aches. Good times. That’s the kind of sinus people talk about, but a sinus is any kind of space, cavity, or passage in a person's body.

When you hear the word sinus, you probably think of the sinuses that can become infected if you have a bad enough cold. You might get a sinus headache when your nose is stuffed up, for example. There are many other sinuses in your body, believe it or not, from the cavernous sinus in your skull to the renal sinuses in your kidneys. The word sinus means "bend, fold, or curve" in Latin.

Definitions of sinus

1. noun

   an abnormal passage leading from a suppurating cavity to the body surface
   synonyms: fistula

   type of:

   passage, passageway

   a path or channel or duct through or along which something may pass
2. noun

   any of various air-filled cavities especially in the bones of the skull
   types:

   ethmoid sinus, ethmoidal sinus, sinus ethmoidales

   a sinus of the meatuses of the nasal cavity (behind the bridge of the nose)

   frontal sinus

   one of a pair of cavities in the frontal bone

   maxillary sinus

   one of a pair of sinuses forming a cavity in the maxilla

   nasal sinus, paranasal sinus, sinus paranasales

   any of the paired sinuses in the bones of the face adjacent to the nasal cavity that are lined with mucous membrane that is continuous with the lining of the nasal cavities

   type of:

   bodily cavity, cavity, cavum

   (anatomy) a natural hollow or sinus within the body
3. noun

   a wide channel containing blood; does not have the coating of an ordinary blood vessel
   synonyms: venous sinus

   types:

   cavernous sinus, sinus cavernosus

   either of a pair of large venous sinuses in the cranial cavity

   coronary sinus, sinus coronarius

   a short sinus receiving most of the veins of the heart; empties into the right atrium

   sigmoid sinus, sinus sigmoideus

   an S-shaped dural sinus on the temporal and occipital bones

   sinus rectus, straight sinus, tentorial sinus

   an unpaired sinus of the dura mater

   sinus transversus, transverse sinus

   a paired dural sinus; terminates in the sigmoid sinus

   type of:

   canal, channel, duct, epithelial duct

   a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance