adj. 1 a of or written in a margin. b having marginal notes. 2 a of or at the edge; not central. b not significant or decisive (the work is of merely marginal interest). 3 Brit. (of a parliamentary seat or constituency) having a small majority at risk in an election. 4 close to the limit, esp. of profitability. 5 (of the sea) adjacent to the shore of a State. 6 (of land) difficult to cultivate; unprofitable. 7 barely adequate; unprovided for. marginal cost the cost added by making one extra copy etc. marginality n. marginally adv.
[ med.L marginalis (as MARGIN) ]