Flint (noun)

1. A hard, fine-grained, sedimentary rock that is the chief source of silicon dioxide, occurs in various forms, and is used for making tools, weapons, and building materials.
2. A piece of flint used for striking fire.

Origin:

Old english flint, of germanic origin; related to dutch vlint and german flinte.

Examples:

1. Flint is often used to make knives and arrowheads.
2. He struck a flint and steel together to start a fire.
3. The flint wall was built by ancient people.
4. The flint knapping technique was used to make arrowheads.
5. The flint in this area is of high quality and easily worked.