chalk line

chalk´ line`    (chạk´ līn`)

n.	1.	a string impregnated with powdered chalk, used in construction to mark a straight line on a surface, such as a wall. The string is held taut on the surface between the two end points of the line to be made, the center of the line is drawn away from the surface, and the string is released and snapped against the surface, leaving a line of chalk in the desired location.
	2.	the line of chalk on a surface left by a chalk line{1}.

Thesaurus

Noun

1.

chalk line - a chalked string used in the building trades to make a straight line on a vertical surface snap line, snapline string, twine - a lightweight cord