marker

n. sign; scorekeeper; symbol that indicates a place reached, milestone; tombstone; felt-tipped pen that usually has a broad tip

Marker may refer to:Marker (film), an Action movie with Steven SeagalMarker (alpine bindings), a company specializing in bindingsMarker (linguistics), a morpheme that indicates some grammatical functionMarker (telecommunications), a special-purpose computerMarker (TV series), a 1995 American drama on UPNMarker, Norway
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n. marker, felt-tipped pen that usually has a broad tip; scorekeeper (Sport)

(n.)
The soldier who forms the pilot of a wheeling column, or marks the direction of an alignment.
  

(n.)
One who or that which marks.
  

(n.)
One who keeps account of a game played, as of billiards.
  

(n.)
An attachment to a sewing machine for marking a line on the fabric by creasing it.
  

(n.)
A counter used in card playing and other games.
  

An identifiable heritable spot on a chromosome. A marker can be an expressed region of DNA (a gene) or a segment of DNA with no known coding function. All that matters is that the marker can be monitored.