The word "march" derives ultimately from a
Proto-Indo-European root *mereg-, meaning "edge, boundary". The root *mereg- produced
Latin margo ("margin"),
Old Irish mruig ("borderland"), and
marz ("borderland"). The
Proto-Germanic *marko gave rise to the
Old English word mearc and
Frankish marka, as well as
Old Norse mörk meaning "borderland, forest",
derived form merki "boundary, sign",
 denoting a borderland between two centres of power.
It seems that in Old English "mark" meant "boundary" or "sign of a boundary", and the meaning only later evolved to encompass "sign" in general, "impression" and "trace".
Anglo-Saxon kingdom of
Mercia took its name from
West Saxon mearc "marches", which in this instance referred explicitly to the territory's position on the Anglo-Saxon frontier with the
Romano-British to the west.
During the Frankish
Carolingian Dynasty, usage of the word spread throughout Europe.
The name Denmark preserves the Old Norse cognates merki ("boundary") mörk ("wood", "forest") up to the present. Following the
Anschluss, the Nazi German government revived the old name 'Ostmark' for Austria.