sinus — English Dictionary

Noun

1. A pouch or cavity in a bone or other tissue, especially one in the bones of the face or skull connecting with the nasal cavities (the paranasal sinus).

2. An irregular venous or lymphatic cavity, reservoir, or dilated vessel.

3. An irregular venous or lymphatic cavity, reservoir, or dilated vessel. Relating to or denoting the sinoatrial node of the heart or its function of regulating the heartbeat.

   Usage

   • attributive

4. An abnormal cavity or passage such as a fistula, leading from a deep-seated infection and discharging pus to the surface.

5. A rounded notch or depression between two lobes or teeth in the margin of a leaf or petal.

6. A bay of the sea; a recess in the shore.

7. Synonym of sine.

   Examples

   More examples (1)

   So, in the helicopteron, as the helix is at the same time a sustaining plane, it should be likened to a surface moving horizontally, and in which, consequenty, the resistance to motion will be to the lifting power as the sinus is to the cosinus of the angle formed by such plane with the horizon.

   The variations are described in terms of cycles of sinuses and cosinuses.

   More examples (1)

   Basically, the rotation of the matrix of the factor loadings L represents its post-multiplication, i.e. L* = LO by the rotation matrix O, which itself resembles one of the matrices included in the classical rotational Lie groups SO(m) (containing the specific m–fold combination of sinuses and cosinuses.

Noun

1. an abnormal passage leading from a suppurating cavity to the body surface

   Synonyms

   fistula

   Broader terms

   passagepassageway

2. any of various air-filled cavities especially in the bones of the skull

   Broader terms

   cavitybodily cavitycavum

3. a wide channel containing blood; does not have the coating of an ordinary blood vessel

   Synonyms

   venous sinus

   Broader terms

   ductepithelial ductcanalchannel