Bing found the following results
Manifold Definition & Meaning - Merriam-Webster
Manifold - Wikipedia
MANIFOLD | English meaning - Cambridge Dictionary
Manifold -- from Wolfram MathWorld
MANIFOLD Definition & Meaning | Dictionary.com
Manifold - Encyclopedia of Mathematics
Manifold | Differential Geometry, Topology & Algebra | Britannica
MANIFOLD | definition in the Cambridge English Dictionary
An Introduction to Manifolds | SpringerLink