Sinus
/ˈsaɪ.nəs/noun
A curve, hollow, or cavity; in anatomy, a cavity or channel in a bone or tissue.
Did you know?Latin sinus could mean a fold in a garment, a bay, a hollow, or the bosom, and that same “curved-in” image later helped name the air-filled spaces in the skull.
Etymological Timeline
Proto-Indo-European
PIE
*kei-
“to lie down, rest, or be bent/curved”
Latin
Latin
sinus
“a fold, curve, lap, bosom, or hollow; also a bay or gulf”
Late Latin
Latin
sinus
“a hollow space or cavity, including anatomical uses”
Old French
Old French
sinus
“a hollow or recess”
Modern English
English
sinus
“a cavity or channel, especially one in the skull or tissue”