rapid

nouns

a part of a river where the current is very fast

rapid

is a part of

a large natural stream of water (larger than a creek)

"the river was navigable for 50 miles"

is a type of (narrower)

a navigable body of water

done or occurring in a brief period of time

"a rapid rise through the ranks"

rapid

is derived from

is derived from

is similar to

acting or moving or capable of acting or moving quickly

"fast film"; "on the fast track in school"; "set a fast pace"; "a fast car"

characterized by speed; moving with or capable of moving with high speed

"a rapid movement"; "a speedy car"; "a speedy errand boy"

rapid, speedy

is derived from

is derived from