plural of cross-multiplication (denoting countable instances of the uncountable concept).

present participle of cross-multiply

(mathematics) An instance, or the process, of cross-multiplying.

To set the product of the extremes of a proportion equal to the product of its means.

A burning cross made of wood, historically used to rally troops.

plural of cross-staff

Alternative form of cross-purpose

(geometry) A special number associated with an ordered quadruple of collinear points, particularly points on a projective line, and preserved by the fractional linear transformations.

Able to use, connect, interact, and function universally with various systems.

(transitive, intransitive) To sell (additional products) to existing customers.