wavefront - (physics) an imaginary surface joining all points in space that are reached at the same instant by a wave propagating through a medium. wave front. natural philosophy, physics-the science of matter and energy and their interactions; his favorite subject was physics.avefront - (physics) an imaginary surface joining all points in space that are reached at the same instant by a wave propagating through a medium. wave front. natural philosophy, physics-the science of matter and energy and their interactions; his favorite subject was physics.