Militia (noun)

1. A military force composed of ordinary citizens, typically called upon in times of emergency or unrest.
2. A group of individuals who organize for the purpose of defending their community or country.

Origin:

From latin milites (soldiers), from miles (soldier).

Examples:

1. The governor called up the state militia to assist with disaster relief efforts.
2. The town formed a militia to protect themselves from bandits and outlaws.
3. The Second Amendment to the US Constitution protects the right to bear arms and form militias.
4. The militia was unable to repel the invading army and the town fell.
5. The militia was disbanded after a series of scandals and accusations of corruption.