noun
(linguistic morphology) A bound morpheme added to a word’s stem, such as a prefix or suffix.
(now uncommon) That which is affixed; an appendage.
(mathematics) The complex number a+bi associated with the point in the Gauss plane with coordinates (a,b).
(decorative art) Any small feature, as a figure, a flower, or the like, added for ornament to a vessel or other utensil, to an architectural feature.
verb
(transitive) To attach.
(transitive) To subjoin, annex, or add at the close or end; to append to.
(ditransitive, with on or upon) To fix or fasten figuratively.