- Items or installations that are below grade or ground level.
- noun a movement or group that is separate from the prevailing social or artistic environment and often exerts a subversive influence
- adjective constructed or designed to operate beneath the surface of the ground
- adjective relating to a group or movement which is working secretly against the established authority or an occupying power
- noun (belonging to) the ‘alternative society’ or counterculture, as opposed to bourgeois society. A term from the 1960s adopted from the wartime usage when applied to clandestine resistance movements. (The term ‘underground railroad’ was earlier used for the system of sympathizers/safe houses by which escaped slaves were taken from the southern states to the North before emancipation.).
- noun a railway system which runs in a tunnel under the ground