In linguistic geography, what does an isogloss denote?

• A. A boundary of climate zones.
• B. A boundary separating areas with different usage of a linguistic feature.
• C. A line demarcating political borders.
• D. A map scale indicator.

Answer: (B)

An isogloss marks a boundary separating areas where a particular linguistic feature is used differently. It shows how language varies across space, such as where one region uses a word, pronunciation, or grammatical form that another region does not. This line is specifically about language, not about climate zones, political borders, or map scale. When several isoglosses run close together, they can outline broader dialect regions, illustrating how a feature diffuses across a landscape.