infrastructure-n; 2 Senses

Sense Number 1: necessities

Commentary: the stock of basic facilities and capital equipment needed for the functioning of a country or area

America's infrastructure relies heavily on oil.
Infrastructure can refer to roads, bridges, and rail lines necessary for industrial economy.

WordNet 2.0 Sense Numbers: 2

Sense Number 2: substructure

Commentary: the basic structure or features of a system or organization

The financial infrastructure the large corporation was composed of many different departments.
Environmentalism has an infrastructure of groups, committees, and admirers.

WordNet 2.0 Sense Numbers: 1