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Substantiivi

1. (set theory, of two sets X and Y) The set of all possible ordered pairs of elements, the being first from ${\displaystyle X}$, the second from ${\displaystyle Y}$, written ${\displaystyle X\times Y}$. Formally, the set \{(x,y)\; |\; x∈ X \; \text{and} \; y∈ Y\}.
2. (databases) All possible combinations of rows between all of the tables listed.
3. (geometry, of an m-dimensional space X and an n-dimensional space Y) An (m+n)-dimensional space, formally composed of all possible ordered pairs of points from ${\displaystyle X}$ and ${\displaystyle Y}$, but thought of as an independent (m+n)-dimensional space (in the sense that if, e.g. ${\displaystyle X}$ and ${\displaystyle Y}$ are vector spaces, the elements of ${\displaystyle X\times Y}$ are thought of as (m+n)-tuples instead of ordered pairs) and written ${\displaystyle X\times Y}$.
4. (mathematics) Any of several generalizations of the set-theoretic sense, especially one which shares the geometrical intuition outlined above, i.e. one such that the product can be thought of as an object in its own right and not just as a set of pairs.