Final answer:
The relationship between the terms inner planet and terrestrial planet is that the inner planets are also known as the terrestrial planets.
Step-by-step explanation:
The relationship between the terms inner planet and terrestrial planet is that the inner planets are also known as the terrestrial planets. The four planets closest to the Sun, namely Mercury, Venus, Earth, and Mars, are considered inner or terrestrial planets. These planets are relatively small and composed primarily of rock and metal, with solid surfaces that bear the records of their geological history.