Definitions for date line
Random House Webster's College Dictionary
Ref: International Date Line.
Origin of date line:
date•lineˈdeɪtˌlaɪn(n.; v.)-lined, -lin•ing.
(n.)a line at the beginning of a news dispatch, giving the place of origin and usu. the date.
(v.t.)to furnish (a news story) with a dateline.
Origin of dateline:
dateline, date line, International Date Line(noun)
an imaginary line on the surface of the earth following (approximately) the 180th meridian
Dictionary of Military and Associated Terms
See international date line.