The stibadium (plural: stibadia) is a later form of the Roman lectus triclinaris, the reclining seat used by diners in the triclinium. Originally, the lecti were arranged in a group of three in a semi-circle. The stibadium was a single semi-circular couch, fitting up to a dozen people, which replaced the triple group of lecti in the dining-room, frequently in alcoves around the centre of the room.
The stibadium was originally an outdoor seat but was introduced indoors in the 2nd-3rd centuries B.C. because the shape was more convenient for entertaining and as triclinia became larger and more elaborate.
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