1. a director;〔大学などの〕a trustee
    • 理事[理事長]になる
    • become 「a member [the chairperson] of the board of directors [trustees]
    • 常任理事
    • an executive director
  1. 理事会a board of directors [trustees]
  1. 理事国a member of a council
    • 国連安全保障理事会常任[非常任]理事国
    • a permanent [nonpermanent] member of the UN Security Council