Radio and television broadcasts and cellular telephone messages travel through the air on radio waves. Rope waves travel along the length of the rope and are one-dimensional. Water waves generated by a falling stone form circles that spread out over the surface of the pond. These waves are two-dimensional. Sound originates at a point and travels equally strongly in all directions.
Sound waves are spherical and three-dimensional.
There are two main types of waves, longitudinal and transverse, depending on the motion of the medium. In transverse waves, the medium moves perpendicular to the direction in which the wave travels. For example, a rope wave is a transverse wave because the rope moves up and down while the wave moves from one end of the rope to the other. Light waves and other electromagnetic waves are also transverse waves. Waves that travel in the same direction that the medium moves are longitudinal waves.