sinus

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).

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.

    1. (physiology, attributive) Relating to or denoting the sinoatrial node of the heart or its function of regulating the heartbeat.

  3. An abnormal cavity or passage such as a fistula, leading from a deep-seated infection and discharging pus to the surface.
  4. A rounded notch or depression between two lobes or teeth in the margin of a leaf or petal.
  5. A bay of the sea; a recess in the shore.
  6. Synonym of sine.
    • 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 variations are described in terms of cycles of sinuses and cosinuses. - 1996, Pentti Zetterberg, Matti Eronen, Markus Lindholm, “Construction of a 7500-Year Tree-Ring Record for Scots Pine (Pinus sylvestris, L.) in...
    • 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...

    Synonyms: sine

Origin

Learned borrowing from Latin sinus (“a bent surface, curve, hollow”). Doublet of sine.

Forms

sinuses

Derived

confluence of sinuses dural sinus dural venous sinus extrasinus inferior petrosal sinus inferior sagittal sinus intrasinus nonsinus parasinus pyriform sinus sick sinus syndrome sinal sino- sinu- sinuso- sinus brady sinuscope sinusectomy sinusitis sinuslike sinus node sinusoid sinusopathy sinusotomy