* Decahedron: A polyhedron with ten faces.
* Decagram: A unit of mass equal to 10 grams.
* Decaliter: A unit of volume equal to 10 liters.
* Decameter: A unit of length equal to 10 meters.
* Decathlon: An athletic competition consisting of ten events.
* Decapitate: To behead.
* Decadence: A state of moral or cultural decline.
* Decalogue: The Ten Commandments.
* Decameron: A collection of 100 stories by Boccaccio.
The prefix "deca-" comes from the Greek word "deka", meaning "ten". It is often used to indicate a quantity of ten, or a unit of measurement that is ten times larger than the base unit.