A more thorough explanation:

A deadly weapon is an object, substance, or device that can cause death or serious injury when used in a certain way. It can be a traditional weapon like a gun or knife, or even something as simple as a rock or a person's hands.

For example, if someone uses a large rock to hit another person in the head, causing serious injury or death, the rock can be considered a deadly weapon. Similarly, if someone uses their hands or fists to attack someone and causes serious injury or death, their hands can be considered deadly weapons.

When a person is charged with a crime like assault with a deadly weapon, the prosecutor must prove that the defendant used a weapon that was capable of causing death or serious injury. This can be determined by examining the physical qualities of the weapon, the manner in which it was used, and the injuries sustained by the victim.

Some jurisdictions have specific laws that list certain weapons as "deadly weapons per se," meaning that they are automatically considered deadly regardless of how they are used. For example, firearms are commonly considered deadly weapons per se.

Overall, a deadly weapon is any object or device that can cause death or serious injury when used in a certain way, and its use in a crime can result in serious legal consequences.