Answer: isotherm

AnswerCrossword Clue
ISOTHERMWeather map line
ISOTHERMWeather-map feature
ISOTHERMLine on a weather map
ISOTHERMLine on a weather map showing equal temperatures
ISOTHERMLine on a map is additional mile (8)
isothermcurve on which every point represents the same temperature
isothermline on a weather map or chart connecting points having equal temperature
isotherma contour line of equal temperature