Atlas and Meridian are the names of the two small lizard creatures that once surrounded the mini-map on the user interface. Their identities were revealed in an early issue of Postbag from the Hedge. Atlas and Meridian, according to the Postbag, were offered the job with the promise of "seeing the world". However, they soon discovered that this just meant holding the map for the player to see.
Atlas and Meridian's names are both map-related terms. In geography, the meridian is an imaginary line that runs from the North Pole to the South Pole. It is also an astronomical term, referring to an imaginary circle in the celestial sphere. An atlas is a collection of maps, usually placed in a book. Also, in real-world Greek mythology, Atlas was a titan condemned to literally hold the sky on his shoulders, while in RuneScape, Atlas must, in a way, hold the world up.
When the user interface changes occurred, Atlas and Meridian no longer appeared on the user interface, and were instead replaced with a dragon. The addition of RuneScape High Detail would then replace the dragon with an icon that led to the World map.