dateline n 1: an imaginary line on the surface of the earth following (approximately) the 180th meridian [syn: {dateline}, {date line}, {International Date Line}] 2: a line at the beginning of a news article giving the date and place of origin of the news dispatch v 1: mark with a date and place; "dateline a newspaper article" [syn: {dateline}, {datemark}, {date-mark}]