Map line (6)
'map line' is the definition.
(line indicating pressure on a map)
This is the entire clue.
(Other definitions for isobar that I've seen before include "Line on map showing barometric pressure" , "Weather map feature" , "meteorologist's line" , "Line on map showing atmospheric pressure" , "Line connecting points of equal air pressure" .)
'map line' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for street that I've seen before include "See 14" , "Part of motorist's route" , "- Arab; - light" , "City thoroughfare" , "Public road in a conurbation" .)