(mathematics) An operation, written using the symbol +, that produces the sum of two operands

Initialism of attention deficit disorder. / Initialism of accidental death and dismemberment.

(algebra) An element of an algebraic structure, generally denoted 0, which is an identity for an additive operation (generally denoted +). That is, x + 0 = 0 + x = x for any x in the structure.

Something to be added; especially text added as an appendix or supplement to a document. / A postscript.

(music) A tempo mark directing that a passage is to be played rather slowly, leisurely and gracefully. / (music) A passage having this mark.

(music) Played rather slowly.

(music) Describing a passage having this mark.

Made of adamant, or having the qualities of adamant; incapable of being broken, dissolved, or penetrated. / Like the diamond in hardness or luster.

An old saying which has obtained credit by long use. / An old saying which has been overused or considered a cliché; a trite maxim.

(Abrahamic religions) The first man and the progenitor of the human race. / A male given name from Hebrew. / (figuratively) Original sin or human frailty.