Benrath line, a term of German linguistics (the maken-machen isogloss)
The La Spezia–Rimini Line (sometimes also referred to as the Massa–Senigallia Line), in the linguistics of the Romance languages, is a line that demarcates a number of important isoglosses that distinguish Romance languages south and east of the line from Romance languages north and west of it.
In Aragon, the dialect in Ribagorza can be clustered into 2 main groups Upper and Lower Ribagorçan defined by an isogloss line running east-west from the Turbón mountain.