Durable goods are just that: hard goods; they don't wear out quickly and can be used over and over again for at least several years. Think your car, TV, refrigerator or computer. These are certainly not disposable, one-time use items.

The opposite of a hard good is (surprise!) a soft good or, if you like, a non-durable good. These are products you use once, like your lunch at McDonald's, the gas in your car and the ugly sweater your grandmother bought you for your birthday. These items have an intended lifespan short of three years, or are consumed immediately.

Investors pay attention to the monthly durable orders report released by the Commerce Department around the end of each month. When durable goods are strong, it means that U.S. manufacturing is humming along, though economists tend to parse the numbers pretty closely. Big-ticket items can skew the overall results, since an order for, say, 75 Boeing 747s has a bigger impact than 75 iPods. Luckily, the data lets economists break down the sectors.