Final answer:
The term describing the deviation of one axis from another parallel axis in physics is the Parallel-Axis Theorem, which is crucial in calculating moments of inertia in rotational motions.
Step-by-step explanation:
The term used to describe the amount by which one axis deviates from another parallel axis is known as the Parallel-Axis Theorem. This theorem is particularly useful in physics when calculating moments of inertia in rotational motions. If we have an object with mass m and we know the axis through the object's center of mass, we can apply the Parallel-Axis Theorem to find the moment of inertia about any other axis parallel to it and a distance d away. The theorem simplifies the calculation of moments of inertia which are crucial for understanding rotational dynamics.