noun
flint
FLINT/flɪnt/
A very hard stone that produces sparks when struck with steel.
The flint sends out sparks where it meets the steel.

Etymology
Old English flint already named stone distinguished by hardness and by giving off sparks when struck. The selected meaning preserves those same defining physical properties.
In context
I got my flint and my steel. Struck together, they spark. The trick though is to catch one of those sparks and to keep it alight.
More examples
- They found a sharp piece of flint in the field.
- An ancient tool had been chipped from flint.
- He carried flint and steel for lighting fires.
Forms
flint · flints
flinty adjective — hard like flint
Similar words
- chert
- A broader closely related category of hard silica-rich rock.