Something added to complete a thing, make up for a deficiency, or extend or strengthen the whole.
A section added to a book or document to give further information or to correct errors.
A separate section devoted to a special subject inserted into a periodical, such as a newspaper.
Mathematics The angle or arc that when added to a given angle or arc makes 180° or a semicircle. Also called supplementary angle.
tr.v.
(-měnt') sup·ple·ment·ed, sup·ple·ment·ing, sup·ple·ments To provide or form a supplement to.
[Middle English, from Old French, from Latin supplēmentum, from supplēre, to complete; see supply.] sup'ple·men·tar'i·ty (-târ'ĭ-tē) n., sup'ple·men'ta·ry (-měn'tə-rē, -trē), sup'ple·men'tal (-měn'tl) adj., sup'ple·men·ta'tion (-měn-tā'shən) n.