hyperboloid - Wiktionary, the free dictionary
From Wiktionary, the free dictionary

hyperboloid (plural hyperboloids)
- A particular surface in three-dimensional Euclidean space, the graph of a quadratic with all three variables squared and their coefficients not all of the same sign.
- If the hyperboloid is a connected surface, it is said to be of one sheet; otherwise, it has two components and is said to be of two sheets.
- Like many terms that start with a non-silent h but have emphasis on their second syllable, some people precede hyperboloid with an, others with a.
- quadric surface, quadric
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