marginal
Pronunciation: /ˈmɑːdʒɪn(ə)l/
adjective
- 1relating to or at the edge or margin: marginal notes
- relating to water adjacent to the land’s edge or coast: water lilies and marginal aquatics
- 2minor and not important; not central: it seems likely to make only a marginal difference the cost is negligible, less than marginal
- (of costs or benefits) relating to or resulting from small or unit changes: the issue is to estimate the marginal benefit from the increased frequency of screening examinations against the marginal increased cost
- (of taxation) relating to increases in income: the marginal tax rates on these incomes rise to as much as 80 per cent in some republics
noun

Origin:
late 16th century: from medieval Latin marginalis, from margo, margin- (see margin)