thành lệ 
established rule [ thành ] : (1) citadel, fortress, wall; (2) to, into; (3) to succeed; (4) to become; (5) honest, sincere
[ lệ ] : (1) custom, rule, regulation; (2) tear; (3) to depend on, rely on; servant; (4) to be shy; (5) epidemic; (6) lichee; (7) beautiful; (8) to encourage
Most Common Compounds Set 1:
Most Common Compounds Set 2 :