Chinese words with 序 character meaning (HSK)

顺序

SHUN4, XU4
sequence, order

程序

CHENG2, XU4
procedures, sequence, order, computer program

秩序

ZHI4, XU4
order (orderly, sequence, social), the state (of society)

次序

CI4, XU4
sequence, order

序言

XU4, YAN2
preface, introductory remarks, preamble, prelude

循序渐进

XUN2, XU4, JIAN4, JIN4
in sequence, step by step (idiom), to make steady progress incrementally