noun

• (mathematics, uncountable) The branch of mathematics dealing with spatial relationships.
• (mathematics, often qualified in combination, countable) 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.
• (countable) The observed or specified spatial attributes of an object, etc.
• (algebraic geometry, countable) A mathematical object comprising representations of a space and of its spatial relationships.