Seven
The ancient Greeks thought of seven as a shape with seven sides and
seven corners. Such a shape is called a heptagon, which means “seven
corners.”
Seven seemed like a special, magical number to people of long
ago—perhaps because they noticed that the moon changed shape every
seven days. So they did such things as making a week seven days long and
celebrating their festivals for seven days. Many people still think of
seven as a lucky number.
There are also the seven wonders of the ancient world and expressions
such as “the seven seas.” The color of seven is said to be violet. And
some people think that the number seven belongs to the star group called
Libra, the Scales.
