A weather map line is a line drawn on a weather map to indicate a certain meteorological phenomenon. The term 'weather map line' can refer to a FRONT (FRONT), which is a boundary between two air masses of different densities; an isotherm (ISOTHERM), which is a line connecting points of equal temperature; an isobar (ISOBAR), which is a line connecting points of equal atmospheric pressure; an isochor (ISOCHOR), which is a line connecting points of equal humidity; and an isothere (ISOTHERE), which is a line connecting points of equal wind speed. A coldfront (COLDFRONT) is a type of FRONT that is associated with a drop in temperature.