hyperboloid

UK: /haɪˈpɜːbəˌlɔɪd/ US: (hī pûr′bə loid′)

WordReference Random House Unabridged Dictionary of American English © 2025

hy•per•bo•loid  (hī pûr′bə loid′), n. [Math.]

1. a quadric surface having a finite center and some of its plane sections hyperbolas. Equation:.

• hyperbol(a) + -oid 1720–30

hy•per′bo•loi′dal, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

hyperboloid / haɪˈpɜːbəˌlɔɪd/ noun

1. a geometric surface consisting of one sheet, or of two sheets separated by a finite distance, whose sections parallel to the three coordinate planes are hyperbolas or ellipses. Equations x²/a² + y²/b² – z²/c² = 1 (one sheet) or x²/a² – y²/b² – z²/c² = 1 (two sheets) where a, b, and c are constants