A counter is a piece of scenery found in many stores throughout RuneScape Classic. It has no use in the game.
In Gu'Tanoth ogres use visually counters to sell items such as Rock Cakes. (See: Rock Cake Stall)
Examine: An ogre is selling cakes here
Examine: An ogre is selling items here
In Legends' Guilds' house of Sir Radimus Erkle, the counter is called Grand Viziers Desk.