2. the quantity or amount that completes anything.
3. either of two parts or things needed to complete the whole.
4. full quantity or amount; complete allowance.
5. the full number of officers and crew required to operate a ship.
a. the word or words required to complete the sense of a particular noun, verb or adjective, such as to leave in their intention to leave or They intended to leave.
b. the word or words required to complete the predicate for a particular sense of the verb, such as the old newspapers in He saw the old newspapers, and all over the floor in They lay all over the floor.
c. the adjectival or noun phrase required to complete the predicate of a copular verb, such as old in They seem old, and an old newspaper in It was an old newspaper.
7. Geometry the angular amount needed to bring a given angle to a right angle.
8. Logic, Mathematics all the members of any set, class or space of elements, that are not in a given subset.
a. the noun phrase (or adjective or adverb) within the predicate of a copular verb, which details the grammatical subject, as in They are amazing people, It looks good or The show is over.
b. the phrase or clause that acts as the grammatical object within the predicate, as in We expected an early harvest or We knew it would come early.
c. the noun or adjective which details the grammatical object in constructions, as in They made him president or They made him angry.
d. any obligatory postmodifier of a word, such as of animals in He is fond of animals.
10. Music the interval which added to a given interval completes an octave.
11. Immunology a thermolabile constituent of serum composed of more than twenty proteins which complement the action of the antibody.