WordWeb Online

1. Done or occurring in a brief period of time
   "a rapid rise through the ranks"
    
2. Characterized by speed; moving with or capable of moving with high speed
   "a rapid movement";
   - speedy, nippy [Brit, informal]

1. A part of a river where the current is very fast

Derived forms: rapider, rapidest, rapids

See also: fast

Type of: waterway

Part of: river

Encyclopedia: Rapid