Light has properties and characteristics of both a particle and a wave. They have energy and momentum like a particle, and wavelength and frequency like a wave. In actuality other particles, such as electrons, can also behave as waves , but light is unique in that it is a particle (photon) with zero mass.
On a quantum level, photons are the mediators of the electromagnetic force. That is, they are exchanged by interacting charged particles and carry with them an electromagnetic field.
As waves, rays of light will be reflected, refracted, or diffracted when encountering an interface of two different materials.