相沿成习 xiāng yán chéng xí

DEFINITIONS

  1. well established
  2. accepted as a result of long usage

CHARACTERS

相 xiāng
HSK 3
mutual, reciprocal, each other
沿 yán
HSK 6
follow a course, go along
成 chéng
HSK 3
completed, finished, fixed
习 xí
HSK 1
practice; flapping wings