Inner ear and Outer ear

Inner ear noun - A complex system of interconnecting cavities; concerned with hearing and equilibrium.

Outer ear and inner ear are semantically related. In some cases you can use "Outer ear" instead a noun phrase "Inner ear".

Outer ear noun - The part of the ear visible externally.

Inner ear and outer ear are semantically related. You can use "Inner ear" instead a noun phrase "Outer ear".