Boiled eggs are eggs (typically chicken eggs) cooked by immersion in boiling water with their shells unbroken. (Eggs cooked in water without their shells are known as poached eggs, while eggs cooked below the boiling temperature, either with or without the shell, are known as coddled eggs.) Hard-boiled eggs are either boiled long enough for the egg white and then the egg yolk to solidify, or they are left in hot water to cool down, which will gradually solidify them, while a soft-boiled egg yolk, and sometimes even the white, remains at least partially liquid.
The egg timer was so-named due to its common usage in timing the boiling of eggs. Boiled eggs are a popular breakfast food in many countries around the world.