Question

what do you mean by longitudinal waves

Answer 1

Hey guys this is your answer
a wave vibrating in the direction of propagation.

Answer 2

Longitudinal waves are waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of propagation of the wave. Mechanical longitudinal waves are also called compressionalor compression waves, because they produce compression and rarefaction when traveling through a medium, and pressure waves, because they produce increases and decreases in pressure.