Forty is the number that comes after thirty-nine and before forty-one. It's written as 40 in numerals and represents four groups of ten.

Forty shows up in interesting ways throughout history and culture. In the Bible, it often marks important periods: forty days and nights of rain during Noah's flood, forty years the Israelites wandered in the desert, and forty days Jesus spent fasting in the wilderness. Some historians think ancient peoples used forty to mean “a long time” rather than an exact count.

The number has worked its way into everyday expressions too. When someone takes a short nap, they might call it “forty winks.” In the California Gold Rush of 1849, prospectors who rushed west seeking fortune became known as forty-niners. A forty can also mean a forty-acre plot of farmland.

In sports, forty appears in American football's most famous measurement: the forty-yard dash, which tests how fast players can sprint. Scouts use these times to evaluate athletes' speed and explosiveness. A player who runs a blazing forty becomes highly sought after.