complement >> /ˈkɑmpləmənt/
Definition: [transitive verb] Add to (something) in a way that enhances or improves it; make perfect.
Example: a classic blazer complements a look that's stylish or casual
Definition: [noun] A thing that completes or brings to perfection.
Example: the libretto proved a perfect complement to the music
Definition: [noun] A number or quantity of something, especially that required to make a group complete.
Example: at the moment we have a full complement of staff
Definition: [noun] One or more words, phrases, or clauses governed by a verb (or by a nominalization or a predicative adjective) that complete the meaning of the predicate.
Example: Complement clauses are subordinate clauses that function as complements of a word: that they were too noisy in She told them that they were too noisy.
Definition: [noun] A group of proteins present in blood plasma and tissue fluid which combine with an antigen–antibody complex to bring about the lysis of foreign cells.
Example: An example is a transfusion reaction in which IgG and IgM anti-red-cell antibodies activate complement and cause cell lysis.