What term describes an echo from a sound wave traveling from one medium into another?

The correct term that describes an echo from a sound wave traveling from one medium into another is wave reflection. When a sound wave encounters a boundary between two different media, such as air and water, part of the sound wave is reflected back into the original medium while the rest may be transmitted into the second medium. This reflection of sound creates an echo, which can be identified and measured.

Acoustic impedance is relevant to understanding how sound behaves at the interface of two media, but it specifically refers to how much sound pressure is generated for a given sound wave. Echo location, while related to the use of reflected sound to determine location, does not specifically describe the phenomenon of reflection itself. Sound reception pertains to how sound is perceived or detected by an auditory system but does not describe the physical behavior of sound waves at a boundary. Therefore, wave reflection accurately captures the concept of an echo resulting from sound waves transitioning between different media.