sinus
UK[ˈsaɪnəs]US[ˈsaɪnəs]
n
any of the air-filled cavities in the skull that connect to the nasal passages.
n
a cavity, hollow, or channel in the body, such as a blood sinus.
n
a curve or bend; a sinuous shape.
Etymology
the word 'sinus' was directly borrowed into english from latin, where it meant 'bend, fold, hollow, bay'. the latin term itself is of uncertain origin, though it may be related to the proto-indo-european root swē- meaning 'to bend, to turn'. the anatomical sense, referring to the hollow cavities in the skull, developed in medieval latin from the core idea of a hollow or cavity. this logical progression from a general term for a hollow or curve to a specific medical term illustrates how latin vocabulary was adapted for precise scientific description.
Analysis
the entire word 'sinus' is a simplex loanword from latin. it is not productively segmented into smaller meaningful parts in modern english.
Examples
a severe sinus infection can cause headaches and facial pain.
the coronary sinus is a large vein that collects blood from the heart muscle.
the coastline was a series of deep sinuses and rocky headlands.