恆等

恒等
héngděng
  1. identity ≡ (math., logic)
  2. identical

CEDICT

math

Entry Composition

1 恆 héng
  1. permanent
  2. constant
  3. fixed
  4. usual
  5. ordinary
  6. rule (old)
  7. one of the 64 hexagrams of the Book of Changes (䷟)
2 等 děng
  1. to wait for; to await
  2. by the time; when; till
  3. and so on; etc.; et al.
  4. (bound form) class; rank; grade
  5. (bound form) equal to; same as
  6. (used to end an enumeration)
  7. (literary) (plural suffix attached to a personal pronoun or noun)