東部

1. Origins, structure, and basic meaning

• Structure: The directional noun 東部 (とうぶ) denotes the eastern part of a defined area such as an island or town.
• Basic usage: The whole is linked with の in 島の東部, and the location can modify a feature such as a river.

2. Common pitfalls and similar expressions

• The eastern part within an area
  • It denotes one part of a defined whole such as an island or town, not merely an eastward direction.