A generalized version of the Laplace operator that can be used with Riemannian and pseudo-Riemannian manifolds.

(travel, aviation) A fare construction on a single return ticket where the origin and destination of the first flight are both different from the origin and destination on the return flight.

(travel, aviation) A fare construction where the destination is not the same as the origin point for the return, or where the origin differs from the return destination.

the outside / the outdoors; a space not surrounded by walls; an open space

(idiomatic, of a woman) To open oneself up to sexual intercourse.

plural of open house

plural of open day

A casual event where an institution is open for inspection by anyone interested.

Alternative form of open-mouthed

A type of mine where rock or minerals are extracted from the earth by their removal from an open pit or borrow.