^Capital^ resources form the durable goods of an economy, produced in order to produce yet other goods. Capital goods include machines, roads, computers, hammers, trucks, steel mills, automobiles, washing machines, and buildings. As we will see later, the accumulation of specialized capital goods is essential to the task of economic development.
... 자료: Economics, by Samuelson and Nordhaus, 19th edn. p. 9.
The exposition is the same as its 18th edition: PDF link. (p. 9)