OXFORD DICTIONARY
marginal, 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)
THESAURUS
marginal
bordering, borderline, boundary, bounding, coastal, determinant, determinative, determining, disputable, doubtful, dubious, extreme, fringing, frontier, inferior, infinitesimal, insignificant, limbic, liminal, limit, limiting, littoral, low-priority, minimal, negligible, no great shakes, of no account, of no consequence, of no matter, of no significance, on the edge, questionable, rimming, secondary, skirting, slight, small, terminal, threshold, tiny, unimportant
ROGET THESAURUS
marginal
Edge
N
edge, verge, brink, brow, brim, margin, border, confine, skirt, rim, flange, side, mouth, jaws, chops, chaps, fauces, lip, muzzle, threshold, door, porch, portal, coast, shore, frame, fringe, flounce, frill, list, trimming, edging, skirting, hem, selvedge, welt, furbelow, valance, gimp, border,
marginal, skirting, labial, labiated, marginated.