Edge pairing
From Speedsolving.com Wiki
Edge Pairing is the substep of reduction methods for big cubes in which edges are paired, completing the reduction to 3x3 (plus possible parities).
4x4 Edge Pairing
See main article.
Bigger Cubes
The Big Cubes Edge Pairing method, popularized by bigcubes.com, was the first serious edge pairing method used in speedsolving. For 5x5, Big Cubes is more popular than the less-used and newer AvG Edge Pairing (2 edges at a time), though several world records have been set using the latter, and there are several prominent AvG users today, most notably Erik Akkersdijk. For 6x6 and up, Big Cubes method remains the only competitive edge pairing method.