A "bunny run" is a short errand, usually taken on foot, with the purpose of accomplishing a single task at a specific place and then returning immediately to the point of origin.
Derived from the behavior of a rabbit in venturing out of its burrow for a purpose and then returning to shelter quickly.
The term implies speed of action, and can also be used to describe a short race.
1. Taking a short trip to the store to retrieve a specific item and returning home
2. Leaving work to get a cup of coffee and returning to your desk
3. Leaving your campsite to retrieve wood from a specific place and coming back
Example usage: "Ross made a bunny run to the Kwik-E-Mart to get us a slushie."