*merg-

Proto-Indo-European root meaning "boundary, border."

It forms all or part of: Cymric; demarcation; Denmark; emarginate; landmark; march (v.) "walk with regular tread;" march (n.2) "boundary;" marchioness; margin; margrave; mark (n.1) "trace, impression;" mark (n.2) "unit of money or weight;" marque; marquee; marquetry; marquis; remark; remarkable.

It is the hypothetical source of/evidence for its existence is provided by: Latin margo "margin;" Avestan mareza- "border;" Old Irish mruig, Irish bruig "borderland," Welsh bro "district;" Old English mearc "boundary, sign, limit, mark," Gothic marka "boundary, frontier."