The word was imported from French, where it means subgrade, the native [[material]] underneath a constructed pavement or railway. The word is a combination of the [[Latin]] prefix "infra", [[meaning]] "below" and "[[structure]]". The military sense of the word was probably first used in France, and imported into English around the time of the [[First World War]]. The military use of the term achieved currency in the United States after the formation of [http://en.wikipedia.org/wiki/NATO NATO] in the 1940s, and was then adopted by urban planners in its modern civilian sense by 1970. [6], . | The word was imported from French, where it means subgrade, the native [[material]] underneath a constructed pavement or railway. The word is a combination of the [[Latin]] prefix "infra", [[meaning]] "below" and "[[structure]]". The military sense of the word was probably first used in France, and imported into English around the time of the [[First World War]]. The military use of the term achieved currency in the United States after the formation of [http://en.wikipedia.org/wiki/NATO NATO] in the 1940s, and was then adopted by urban planners in its modern civilian sense by 1970. [6], . |