Rapid \Rap"id\, a. [L. rapidus, fr. rapere to seize and carry off, to snatch or hurry away; perhaps akin to Gr. ?; cf. F. rapide. Cf. Harpy, Ravish.]

1. Very swift or quick; moving with celerity; fast; as, a rapid stream; a rapid flight; a rapid motion.

Ascend my chariot; guide the rapid wheels. --Milton.

2. Advancing with haste or speed; speedy in progression; in quick sequence; as, rapid growth; rapid improvement; rapid recurrence; rapid succession.

3. Quick in execution; as, a rapid penman.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Rapid \Rap"id\, n. [Cf. F. rapide. See Rapid, a.]

The part of a river where the current moves with great swiftness, but without actual waterfall or cascade; -- usually in the plural; as, the Lachine rapids in the St. Lawrence.

Source: Webster's Revised Unabridged Dictionary (1913)