1. the action or process of making or becoming less dense
2. a decrease in the density of something, especially air or gas
Usage: physics

Examples

• The rarefaction of air at high altitudes makes breathing difficult.
• Sound waves consist of alternating compression and rarefaction of air molecules.
• The rarefaction of the gas caused the pressure to drop significantly.
• Mountain climbers experience the effects of atmospheric rarefaction.
• The physicist studied the rarefaction patterns in the sound wave.
• Rarefaction occurs when molecules spread out over a larger volume.