airing, dissemination, public exposure, spreading - the opening of a subject to widespread discussion and debate

facts of life, procreation, reproduction, breeding - the sexual activity of conceiving and bearing offspring

biogeny, biogenesis - the production of living organisms from other living organisms

physical phenomenon - a natural phenomenon involving the physics of matter and energy

Doppler effect, Doppler shift - change in the apparent frequency of a wave as observer and source move toward or away from each other

wave front - all the points just reached by a wave as it propagates