- progression (n.)
[progression 词源字典]
- late 14c., "action of moving from one condition to another," from Old French progression and directly from Latin progressionem (nominative progressio) "a going forward, advancement, growth, increase," noun of action from past participle stem of progredi "go forward," from pro- "forward" (see pro-) + gradi "to step, walk," from gradus "step" (see grade (n.)).[progression etymology, progression origin, 英语词源]