Atriclinium (pl.:triclinia) is a formaldining room in aRoman building.^[1] The word is adopted from theGreektriklinion (τρικλίνιον)—fromtri- (τρι-), "three", andklinē (κλίνη), a sort ofcouch, or ratherchaise longue. Each couch was sized to accommodate a diner who reclined on their left side on cushions while somehousehold slaves served multiple courses brought from theculina, orkitchen, and others entertained guests with music, song, or dance.^[2]: 376

Thetriclinium was characterized by threelecti (singularlectus: bed or couch), calledtriclinares ("of thetriclinium"), on three sides of a low square table, whose surfaces sloped away from the table at about 10 degrees. Diners would recline on these surfaces in a semi-recumbent position. The fourth side of the table was left free, presumably to allow service to the table.^[2]: 376 Usually, the open side faced the entrance of the room. In Roman-era dwellings, particularly wealthy ones,triclinia were common^[2]: 343 and the hosts and guests would recline on pillows whilefeasting.

The Museum ofArcheology inArezzo, Italy and theHouse of Cairo inPompeii offer what are thought to be accurate reconstructions oftriclinia. The custom of usingklinai ("dining couches") while taking a meal rather than sitting became popular among the Greeks in the early seventh century BC. From there, it spread to its colonies in southern Italy (Magna Graecia) and was eventually adopted by theEtruscans.

In contrast to the Greek tradition of allowing only male guests into the formal dining room, calledandrōn, while everyday meals were taken with the rest of the family in theoikos, the Etruscans seem not to have restricted the use of theklinē to the male sex. The Romans may have seen the first diningklinai used by the Etruscans but may have refined the practice when they later came to closer contact with the Greek culture.

Dining was the defining ritual in Roman domestic life, lasting from late afternoon through late at night. Typically, nine to twenty guests were invited, arranged in a prescribed seating order to emphasize divisions in status and relative closeness to thedominus.^[3] As static, privileged space, dining rooms received extremely elaborate decoration, with complex perspective scenes and central paintings (or, here, mosaics).Dionysus,Venus, andstill lifes of food were popular. Middle-class and elite Roman houses usually had at least twotriclinia; it is not unusual to find four or more. Here, thetriclinium maius ("big dining room") would be used for larger dinner parties, which would typically include manyclients of the owner.

Smallertriclinia would be used for smaller dinner parties, with a more exclusive set of guests. Hence, their decoration was often at least as elaborate as that found in largertriclinia. As in the largertriclinia, wine, food, and love were always popular themes. However, because of their association with patronage and because dining entertainment often included recitation ofhighbrow literature likeepics, dining rooms could also feature more "serious" themes. As in many houses in Pompeii, here the smaller dining room (triclinium minus) forms a suite with the adjoiningcubiculum and bath.

In laterrepublican times, after the introduction of round tables ofcitrus wood, the three couches were replaced by one of crescent shape (calledsigma from the form of the Greek letter), which as a rule was only intended to hold five persons. The two corner seats (cornua) were the places of honor that, on the right, were considered superior. The remaining seats were reckoned from left to right so that the least important seat was on the left side of the most important. The use of thesigma continued until theMiddle Ages.^[4]

• Accubitum
• Cyzicene hall
• Domus
• Stibadium
• Klinē

• Triclinium (Plan of a Roman House byBarbara McManus)
• Galleries and plans of Roman triclinia (German)
•   This article incorporates text from a publication now in thepublic domain: "Triclinium".Encyclopædia Britannica. Vol. 27 (11th ed.). 1911. pp. 266–267.