si·nu·soid 
(sīnə-soid′, -nyə-)
(sīnə-soid′, -nyə-)n.
1. Mathematics See sine curve.
2. Anatomy Any of the venous cavities through which blood passes in various glands and organs, such as the adrenal gland and the liver.
[Medieval Latin sinus, sine; see SINE + -OID.]
si′nu·soidal (-soidl) adj.
si′nu·soidal·ly adv.