complementation

Concise Oxford English Dictionary © 2008 Oxford University Press:
complementation/kɒmplɪmenˈteɪʃn/

▶noun

• 1 the action of complementing.

• 2 Grammar all the clause constituents that are governed by a verb.

• 3 Genetics the phenomenon by which the effects of two different non-allelic mutations in a gene are partly or entirely cancelled out when they occur together.