conventionality of simultaneity

The conventionality of simultaneity refers to the idea that whether two events are considered to happen at the same time depends on the measurement method and assumptions used, especially in physics. Because the speed of light is a universal constant, different observers moving relative to each other may disagree on the timing of events. However, the way we synchronize clocks (like using light signals) involves choices that are somewhat arbitrary, making simultaneity partly a matter of convention rather than an absolute fact. This concept highlights that our understanding of "simultaneous" depends on agreed-upon measurement standards rather than an absolute universal truth.