Word

そく
gear; speed (e.g. 4-speed transmission)
Word

高速

こうそく
high speed; high gear; highway; freeway; expressway; motorway
Word

速度

そくど
speed; velocity; rate
Word

快速

かいそく
high speed; celerity; mobility; rapid-service train (not as fast as express); rapid train
Word

早い

速い、疾い、捷い
はやい
fast; quick; hasty; brisk; early (in the day, etc.); premature; (too) soon; not yet; (too) early; easy; simple; quick
Word

急速

きゅうそく
rapid (e.g. progress)
Word

加速

かそく
acceleration; speeding up
Word

速報

そくほう
news flash; prompt report; bulletin; quick announcement
Word

減速

げんそく
deceleration
Word

最速

さいそく
fastest