片腕

1. Origins, structure, and basic meaning

• Structure: 片腕(かたうで) can mean one arm or a trusted key aide.
• Basic usage: It describes an injured arm or a close aide entrusted with important negotiations.

2. Common pitfalls and similar expressions

• One side without specifying which
  • In a physical context, 片腕 means one of the two arms; whether it is the right or left arm is specified separately.
• A metaphor for an aide
  • 社長の片腕 means a capable aide on whom the company president relies, corresponding to right-hand aide in English.