契約者

1. Origins, structure, and basic meaning

• Structure: 契約者 (けいやくしゃ) adds person 者 to contract 契約 to denote the contract holder or contracting party.
• Basic usage: It identifies the person responsible for address changes and identity checks at a service counter.

2. Common pitfalls and similar expressions

• The named holder versus a visitor
  • 契約者本人 specifically emphasizes the person named in the contract, not someone appearing on that person's behalf.