Piezo-electric device cut at a specific resonance frequency, mostly used in oscillators.
A crystal is a piezo-electric device cut at a specific resonance frequency. Due to its high Q-factor and high stability crystals are mostly used in oscillators. Also used to create very narrow-band filters. Frequencies range from a few tens of kHz to a few hundred MHz.
MSP430 32-kHz Crystal Oscillators, TI Application Report