medium an intervening substance through which signals can travel as a means for communication
setting,
scene the context and environment in which something is set; "the perfect setting for a ghost story"
element the most favorable environment for a plant or animal; "water is the element of fishes"
habitat,
home ground the type of environment in which an organism or group normally lives or occurs; "a marine habitat"; "he felt safe on his home grounds"
melting pot an environment in which many ideas and races are socially assimilated
