1911 Encyclopædia Britannica/Hemicycle
HEMICYCLE (Gr. ἡμι-, half, and κύκλος, circle), a semicircular recess of considerable size which formed one of the most conspicuous features in the Roman Thermae, where it was always covered with a hemispherical vault. A small example exists in Pompeii, in the street of tombs, with a seat round inside, where those who came to pay their respects to the departed could rest. An immense hemicycle was designed by Bramante for the Vatican, where it constitutes a fine architectural effect at the end of the great court.