Supplement

noun
1.
something added to complete a thing, supply a deficiency, or reinforce or extend a whole.
2.
a part added to a book, document, etc., to supply additional or later information, correct errors, or the like.
3.
a part, usually of special character, issued as an additional feature of a newspaper or other periodical.
4.
Geometry. the quantity by which an angle or an arc falls short of 180° or a semicircle.
verb (used with object)
5.
to complete, add to, or extend by a supplement.
6.
to form a supplement or addition to.
7.
to supply (a deficiency).
noun (ˈsʌplɪmənt)
1.
an addition designed to complete, make up for a deficiency, etc
2.
a section appended to a publication to supply further information, correct errors, etc
3.
a magazine or section inserted into a newspaper or periodical, such as one with colour photographs issued every week
4.
(geometry)

either of a pair of angles whose sum is 180°
an arc of a circle that when added to another arc forms a semicircle Abbreviation sup, supp

verb (ˈsʌplɪˌmɛnt)
5.
(transitive) to provide a supplement to, esp in order to remedy a deficiency