| Definition -
A geographical boundary that separates the linguistic features that demarcate dialects.
For example, some notable isoglosses are:
(1) the Benrath line, which distinguishes High German from the other West Germanic languages, and
(2) the La Spezia-Rimini Line, which distinguishes Northern Italian dialects from Central ones.
1. Major dialects are usually demarcated by multiple isoglosses.
Etymology - The term derives from the Greek ísos, equal or similar, and glossa, tongue or language.