​Tablinum (or tabulinum, from tabula, board, picture), in Roman architecture, the name given to an apartment generally situated on one side of the atrium and opposite to the entrance; it opened in the rear on to the peristyle, with either a large window or only an anteroom or curtain. The walls were richly decorated with fresco pictures, and busts of the family were arranged on pedestals on the two sides of the room.