Sound is a compressional wave.
transverse
They are transverse waves.
Sound waves are longitudinal waves; they travel from side to side, not up and down like transverse waves.
Sound travels through matter as transverse pressure waves.
Waves are often classified as transverse or longitudinal. The sideways vibrations of a string and the surface waves on water are a good examples of transverse waves. Sound waves in fluids (e.g. sound in air, sound traveling under water) are examples of longitudinal waves. In solids, you can have both transverse and longitudinal waves.
Transverse wave
Surface waves are transverse waves.
Longitudinal waves. The other category of waves, transverse waves, can't travel in a gas. This is valid in the case of mechanical waves; because electromagnetic waves are also transverse waves, and they can travel even in a vacuum.
Sound is a compression wave. Waves are basically movements in the medium through which energy travels. Compression waves cause the medium to move parallel to the energy movement. Electromagnetic waves, although they do not require a medium, move parallel to the transfer of energy.
Transverse Wave
True. The up-down type of wave is called a "transverse wave". Light, for example, is this kind of wave. Sound, however, is a different kind of wave. It is the back-forth type, called "longitudinal", or "compression" waves.
Mechanical waves, such as sound waves and water waves, require a medium (solid, liquid, or gas) to travel through. Electromagnetic waves, like light and radio waves, do not require a medium and can travel through a vacuum.