When light travels from one medium into another it suffers

When light travels from one medium to another, its speed changes due to the difference in refractive indices, causing the light ray to bend. This phenomenon is known as refraction. While reflection can also occur at the interface, the phrase 'from one medium into another' primarily describes transmission across the boundary, which is refraction. Dispersion is a specific type of refraction involving wavelength separation, not always present.