1. An underlying base or foundation of an organization or a system: "The company strived to improve its financial infrastructure of so all of the employees could maintain their jobs."
2. The basic facilities, services, and installations needed for the functioning of a community or society: "Infrastructures include transportation and communications systems, water and power lines, and public institutions consisting of schools, post offices, and prisons."

"More money needs to be spent by the government in order to save the deteriorating infrastructures of the country."

3. Etymology: from 1927, from French infrastructure; from Latin infra-, "below, underneath, beneath" + structure, "a fitting together, adjustment, building"; from structus and struere, "to pile, to build, to assemble".

The installations that form the basis for any operation or system; originally it was in a military sense.