1680s, "large tent of unusual elaborateness," from French marquise (mistaken in English as a plural) "linen canopy placed over an officer's tent to distinguish it from others,' " fem. of marquis (see marquis), and perhaps indicating "a place suitable for a marquis."
By 1812 the English word was used of large wooden structures erected for a temporary purpose (a concert, dinner party, etc.). The extended sense of "canopy over the entrance to a hotel or theater, etc." is recorded by 1912 in American English.
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."