To oscillate means to:

To oscillate specifically refers to the motion of an object swinging back and forth around a central point or equilibrium position. This back-and-forth movement occurs in a consistent and repetitive manner, characterized by a regular rhythm. For instance, a pendulum in a clock exemplifies oscillation as it moves to the left and right of its resting position with equal time intervals.

In contrast, moving in a circular motion involves a path that curves around a point, which does not align with the definition of oscillation. Traveling in a straight line represents a linear motion without the repetitive back-and-forth nature that defines oscillation. Remaining stationary indicates a lack of movement altogether, which also does not fit the concept of oscillation. Therefore, swinging back and forth with a steady rhythm is the accurate representation of oscillation.