n.
a loud and disturbing noise
an illegal enterprise (such as extortion or fraud or drug peddling or prostitution) carried on for profit
同义词：fraudulent schemeillegitimate enterprise
the auditory experience of sound that lacks musical quality; sound that is a disagreeable auditory experience
同义词：noisedissonance
a sports implement (usually consisting of a handle and an oval frame with a tightly interlaced network of strings) used to strike a ball (or shuttlecock) in various games
同义词：racquet
Rackets
Kinks, Rings, and Rackets in Filamentous Structures
Reds or Rackets? The Making of Radical and Conservative Unions on the Waterfront
Nonaxisymmetric phospholipid vesicles: Rackets, boomerangs, and starfish
Emotion Measurements of Tennis Rackets on the basis of the Fractal Analysis of EEG
Probabilities and Decision Rules for the Game of Squash Rackets
The dynamic impact characteristics of tennis balls with tennis rackets
The tennis stroke: an EMG analysis of selected muscles with rackets of increasing grip size.
Central American maras: from youth street gangs to transnational protection rackets
Does illegality breed violence? Drug trafficking and state-sponsored protection rackets
