| Ara Pacis | altar of peace dedicated by Augustus |
| atrium | court of a Roman house near the entrance and open to the sky |
| barrel vault | vault in the form of continuous semicircular sections |
| Trajan | early second-century emperor who conquered Dacia and rebuilt much of Rome |
| basilica | rectangular Roman building used for tribunals with entrance on long side |
| patrician | wealthy landowners |
| plebian | small farmers, merchants, freed slaves |
| coffering | square cutouts in a dome used to lighten the dome |
| Colosseum | large amphitheater or arena |
| Constantine | Roman emperor who recognized Christianity |
| Diocletian | Roman emperor who pulled the empire back together at the end of the third century |
| encaustic | painting technique using hot wax |
| forum | public square in a Roman city |
| groin vault | created by the intersection of two barrel vaults |
| insula | mutistoried Roman apartment block |
| Marcus Aurelius | third-century philosopher-emperor |
| oculus | a round central opening in a dome |
| Pax Romana | peace under the rule of the Roman empire |
| Tetrarchs | four rulers who divided rule of Empire |
| Timgad | north African town with grid pattern layout |