D defs.my
Entry 1 sense Webster, 1913

Sinusoid

/sīn'-əs-oidˌ/ · Si·nus·oid · IPA /ˈsaɪ.nə.sɔɪd/
01 n. The curve whose ordinates are proportional to the sines of the abscissas, the equation of the curve being y = a sin x. It is also called th…
  1. 1.
    The curve whose ordinates are proportional to the sines of the abscissas, the equation of the curve being y = a sin x. It is also called the curve of sines.(Geom.) Also: curve of sines