A sten is a type of gun that was used in the past.
Stens are often thought of as old and dangerous.
Examples:
The soldier held a sten in his hands.
The sten was very loud when it shot.
The sten was used in the war.
I don't want to play with a sten!
In the movie, the hero used a sten to fight the bad guys.
The bad guy had a sten and was very scary.