A wave is any disturbance of the state of a substance ( or field ) which travels through a medium or propagates in space with time, transferring energy from one point to another without the movement of the medium itself.
Reflection and refraction are both characteristic properties of waves, along with interference and diffraction.
Reflection is the bouncing back of waves ( for example light waves ) as they strike a surface. Waves can be reflected from plain and curved surfaces, and the angle of incidence to the normal is always equal to the angle of reflection. Reflection of light can be seen in shaving mirrors and driving mirrors.
Refraction is the change in speed, direction and wavelength of waves as they cross the boundary between two media of different densities. When light passes from a less dense to a denser medium, the refracted ray bends towards the normal and the angle of refraction is less than the angle of incidence, but when it passes from a denser to a less dense medium, the refracted ray bends away from the normal and the angle of refraction is greater than the angle of incidence.
Example, sound waves can be refracted that is why sound is clearer at night than during the day.