adjective
(not comparable) Of, relating to, or located at or near a margin or edge; also figurative usages of location and margin (edge).
(comparable) Determined by a small margin; having a salient characteristic determined by a small margin.
(economics, not comparable) Pertaining to changes resulting from a unit increase in production or consumption of a good.
(sociology) Marginalized.
noun
Something or somebody that is marginal.
(politics) A constituency won with a small margin.