The story
From superellipse + -oid.
Etymology from Wiktionary, CC BY-SA 4.0.
superellipsoid
Today it means: A closed surface, of which the sphere and ellipsoid are special cases, whose parametric equation is x = a.cos^(2/r)t, y = b.cos^(2/r)t, z = c.cos^(2/r)t. Full definition →