One who granny-sits.

plural of aisle sitter

(slang) A theatrical critic.

plural of fence-sitter

plural of hand-sitter

(idiomatic) A person who sits on their hands; one who dawdles or remains idle when action is needed. / (idiomatic) An unenthusiastic or unresponsive member of an audience.

A Lorentzian manifold in Minkowski space which is the analogue of the sphere in ordinary Euclidean space.

plural of de Sitter space

A Lorentzian manifold in Minkowski space which is the analogue of a hyperbola in ordinary Euclidean space.

plural of anti-de Sitter space