Main Entry: hy·per·bo·loid

Pronunciation: \-ˌlȯid\

Function: noun

Date: 1743

: a quadric surface whose sections by planes parallel to one coordinate plane are ellipses while those sections by planes parallel to the other two are hyperbolas if proper orientation of the axes is assumed

— hy·per·bo·loi·dal \(ˌ)hī-ˌpər-bə-ˈlȯi-d^əl\ adjective