sinus

[ sahy-nuh s ]
/ ˈsaɪ nəs /

noun, plural si·nus·es.

a curve; bend.
a curving part or recess.
Anatomy.
  1. any of various cavities, recesses, or passages, as a hollow in a bone, or a reservoir or channel for venous blood.
  2. one of the hollow cavities in the skull connecting with the nasal cavities.
  3. an expanded area in a canal or tube.
Pathology. a narrow passage leading to an abscess or the like.
Botany. a small, rounded depression between two projecting lobes, as of a leaf.

Origin of sinus

1590–1600; < Latin sinus (stem sinu-) bent or curved surface, curve, fold

OTHER WORDS FROM sinus

si·nus·like, adjective

Definition for sinus (2 of 2)

Iridum
[ ir-i-duh m ]
/ ˈɪr ɪ dəm /

noun

Sinus. Sinus Iridum.

Example sentences from the Web for sinus

British Dictionary definitions for sinus

sinus
/ (ˈsaɪnəs) /

noun plural -nuses

anatomy
  1. any bodily cavity or hollow space
  2. a large channel for venous blood, esp between the brain and the skull
  3. any of the air cavities in the cranial bones
pathol a passage leading to a cavity containing pus
botany a small rounded notch between two lobes of a leaf, petal, etc
an irregularly shaped cavity

Word Origin for sinus

C16: from Latin: a curve, bay

Medical definitions for sinus

sinus
[ sīnəs ]

n.

A depression or cavity formed by a bending or curving.
A channel for the passage of blood or lymph, without the coats of an ordinary vessel, such as the blood passages in the gravid uterus or in the cerebral meninges.
Any of various air-filled cavities in the bones of the skull, especially one communicating with the nostrils.
A dilatation in a blood vessel.
A fistula or tract leading to a pus-filled cavity.

Scientific definitions for sinus

sinus
[ sīnəs ]

A cavity or hollow space in a bone of the skull, especially one that connects with the nose.
A channel for the passage of a body fluid, such as blood.