a mathematical object comprising a carrier set (aka underlying set or domain), an optional scalar set, a set of operations (typically binary operations, but otherwise each of finite arity) and a set of identities (axioms) which the operations must satisfy.
Any one of the numerous types of mathematical object studied in algebra and especially in universal algebra;
A mathematical system that deals with spatial relationships and that is built on a particular set of axioms; a subbranch of geometry which deals with such a system or systems.
A mathematical object comprising representations of a space and of its spatial relationships.
The observed or specified spatial attributes of an object, etc.
The branch of mathematics dealing with spatial relationships.