What are longitudinal and transverse wave? and is Sound a longitudinal wave?
A wave in which the vibration of the particles is along the direction of propagation of wave in a to and fro fashion is called longitudinal wave.
Example: Compression and rarefaction waves in a spring, sound waves.
A wave in which the vibration of the particles (in case of mechanical wave) is perpendicular to the direction of propagation of wave is called a transverse wave (In case of electromagnetic wave the oscillation of electric and magnetic field are perpendicular to the direction of propagation of the wave).
Example: Water waves, electromagnetic waves.
Yes, sound is a longitudinal wave.