an·nex • v. / əˈneks; ˈaneks/ [tr.] (often be annexed) append or add as an extra or subordinate part, esp. to a document: the first ten amendments were annexed to the Constitution in 1791. ∎  add (territory) to one's own territory by appropriation: Moldova was annexed by the Soviet Union in 1940. ∎ inf. take for oneself; appropriate. ∎ archaic add or attach as a condition or consequence.• n. / ˈaneks; -iks/ (pl. -nex·es) 1. a building joined to or associated with a main building, providing additional space or accommodations.2. an addition to a document: an annex to the report.DERIVATIVES: an·nex·a·tion / ˌanekˈsāshən; ˌanik-/ n.an·nex·a·tion·ist n. & adj.

annex2 add, attach. XIV. — (O)F. annexer, f. annex-, pp. stem of L. annectere, f. AN-1 + nectere bind (cf. NEXUS).
So annexation XV (first in Sc.). — medL.

annex1 something annexed XVI; supplementary building (usu. annexe) XIX. — F. annexe — L. annexum, sb. use of pp. of annectere (see next).