matching

The same as another; sharing the same design.

We bought a new sofa and matching armchairs.

[...] the Class 142s and 143s have at times sported a number of advertising liveries [...]. The two cars of Arriva Trains Wales 142081 were certainly not a matching pair when photographed in 2005.

That constitutes part of a pair with something else; complementary.

I greet you across the miles and hold out my hand to you and wish you many sunlit days and matching moonlit nights.

The process by which things are matched together or paired up.

A set of independent edges in a given graph, i.e. a set of edges which do not intersect, such that pairs of vertices are "matched" to each other one to one.