Chinese

		appointment, arrangement
trad. (約定俗成)		約定	俗成
simp. (约定俗成)		约定	俗成

Adjective

約定俗成

1. (idiomatic) conventional; customary; socially fixed; having an unwritten law

   元宵節賞花燈是約定俗成的習俗。 [MSC, trad.]

   元宵节赏花灯是约定俗成的习俗。 [MSC, simp.]

   Yuánxiāojié shǎng huādēng shì yuēdìngsúchéng de xísú. [Pinyin]

   It is customary to put up lanterns during the Lantern Festival.