compressional wave; longitudinal wave
Physics term for a wave in which particle displacement is parallel to the direction of propagation, creating alternating regions of compression and rarefaction. Used in acoustics, seismology, and solid mechanics.
Sound waves travel through air as compressional waves.
Seismic P-waves are a type of longitudinal wave.
Compound of 疎密 (そみつ, 'sparseness and density') + 波 (は, 'wave'), literally 'sparse-dense wave', referring to the alternating regions of compression and rarefaction.