action - something done (usually as opposed to something said); "there were stories of murders and other unnatural actions"

interplay - reciprocal action and reaction

contact - close interaction; "they kept in daily contact"; "they claimed that they had been in contact with extraterrestrial beings"

interchange, reciprocation, give-and-take - mutual interaction; the activity of interchanging or reciprocating

natural philosophy, physical science, physics - the science of matter and energy and their interactions

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

electromagnetic interaction - an interaction between charged elementary particles that is intermediate in strength between the strong and weak interactions; mediated by photons

gravitational interaction - a weak interaction between particles that results from their mass; mediated by gravitons

color force, strong force, strong interaction - (physics) the interaction that binds protons and neutrons together in the nuclei of atoms; mediated by gluons

weak force, weak interaction - (physics) an interaction between elementary particles involving neutrinos or antineutrinos that is responsible for certain kinds of radioactive decay; mediated by intermediate vector bosons