noun
outer garment; overgarment
Refers to a garment worn over other clothes, such as a coat, jacket, or outer layer. Not as common as 上着 (うわぎ) in everyday speech, but understood.
寒いので、上服を着て出かけます。
It's cold, so I'll go out wearing an outer garment.
この上服は軽くて暖かい。
This outer garment is light and warm.