По дороге домой я решил заехать в аптеку за лекарством.

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Breakdown of По дороге домой я решил заехать в аптеку за лекарством.

• в: to
• за: for
• домой: home

Questions & Answers about По дороге домой я решил заехать в аптеку за лекарством.

Why does по дороге домой mean on the way home?

This is a very common Russian expression.

• по дороге literally means along the road / on the way
• домой means homeward / to home

Together, по дороге домой means on the way home.

Russian often uses this kind of compact phrase where English would prefer a fuller expression.

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What case is дороге, and why is it used after по?

Дороге is in the dative singular.

The preposition по often takes the dative when it means things like:

• along
• according to
• during / in the course of
• in set phrases like on the way

So:

• дорога = road, way
• по дороге = along the road / on the way

This is something learners usually just get used to as a fixed pattern: по дороге + destination.

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Why is it домой, not дома?