Annotation in geolocation refers to the process of adding additional information to a specific location, such as a label, note or image. This can include information such as the names of streets and buildings, points of interest, and other landmarks. Annotation can be used to enhance the usability and functionality of a geolocation system, such as by providing users with more detailed information about a particular location or by making it easier to navigate through an unfamiliar area. Annotation can be done manually or by using automated tools.

For example, an annotation on a map of a city could include the name of a popular tourist attraction, such as "Eiffel Tower" along with its location coordinates. This information can be used by users of the map to easily identify and locate the attraction, as well as providing additional context or background information about it. Annotation can also include adding information like opening hours, contact details, or even reviews and ratings of the location.