step (n.)youdaoicibaDictYouDict[step 词源字典]
Old English steppa (Mercian), stæpe, stepe (West Saxon) "stair, act of stepping," from the source of step (v.). Compare Old Frisian, Middle Dutch, Dutch stap, Old High German stapfo, German Stapfe "footstep"). From late Old English as "degree on a scale." Figurative meaning "action which leads toward a result" is recorded from 1540s. In dancing, from 1670s. Meaning "type of military pace" is from 1798. Warning phrase watch your step is attested from 1911. Step by step indicating steady progression is from 1580s. To follow in (someone's) steps is from mid-13c.[step etymology, step origin, 英语词源]