Ranger (noun)

1. A person employed to protect and preserve an area of natural beauty, wildlife, or historical interest, especially a national park or forest.
2. A soldier or member of a military unit responsible for security, reconnaissance, and patrol duties in a designated area.
3. A member of a police force who patrols a particular area or neighborhood.

Origin:

Mid 16th century: from middle french rangeur, from ranger 'to range', from old french rengier 'to put in a row', from rang 'a row'. the original sense was 'a person who arranges troops in order', later 'a soldier who ranges over a district on horseback', hence the current sense.

Examples:

1. The park ranger gave a talk about the wildlife in the park.
2. The army ranger was trained for special missions.
3. The neighborhood ranger was known for his friendly and approachable demeanor.
4. The ranger led a group of hikers on a trail through the mountains.
5. The ranger explained the rules and regulations of the park to the visitors.