Time dilation in Special Relativity (SR) and General Relativity (GR), discovered by Albert Einstein, is conventionally introduced through distinct mechanisms: relative velocity in SR and gravitational potential in GR. In contrast, this paper proposes a unified conceptual framework for interpreting time dilation in both SR and GR based on a single geometric principle, illustrated using a common light-clock model. The guiding heuristic is "longer path = slower tick." In SR, relative motion causes the light pulse in a moving light clock to follow a longer diagonal spacetime path between successive reflections, leading to time dilation. In GR, spacetime curvature(geodesics) generated by mass—energy causes the light pulse to follow a longer curved path between equivalent clock events, likewise resulting in time dilation. Rather than interpreting gravitational time dilation solely through abstract expressions involving gravitational potential, this approach emphasizes a geometric interpretation in which time dilation arises from the increased spacetime path length traversed by the light pulse in curved spacetime. This interpretation is consistent with the experimentally verified Shapiro time delay, which demonstrates that a light pulse requires additional propagation time when passing through regions of strong gravitational curvature near a massive body. This framework is intended as a heuristic and interpretive aid and it does not replace the full tensorial formulation of SR and GR or their quantitative predictions derived from the Einstein field equations.