pegasus (pegasi, pl.) a winged divine horse; sired by Poseidon, in his role as horse-god

Peleus father of Achilles; his wedding to the sea nymph Thetis was well attended by the gods, and a disagreement between them at the event eventually led to the Trojan War; the guardian dragon at Camp Half-Blood is named after him

Persephone the Greek goddess of springtime and vegetation; daughter of Zeus and Demeter; Hades fell in love with her and abducted her to the Underworld to become his wife and queen of the Underworld

Phaethon the demigod son of Helios, Titan of the Sun; he accidentally scorched the Earth when he drove Helios’s sun chariot, and Zeus killed him with lightning as a result

Pluto the Roman god of death and ruler of the Underworld. Greek form: Hades

Poseidon the Greek god of the sea; son of the Titans Kronos and Rhea, and the brother of Zeus and Hades. Roman form: Neptune

praetor an elected Roman magistrate and commander of the army

Primordial Chaos the first thing ever to exist; a void from which the first gods were produced

princeps Latin for first citizen or first in line; the early Roman emperors adopted this title for themselves, and it came to mean prince of Rome

Pythia the priestess of Apollo’s prophecies; the name given to every Oracle of Delphi

Python a monstrous serpent that Gaea appointed to guard the Oracle at Delphi

River Styx the river that forms the boundary between Earth and the Underworld

roc an enormous bird of prey

Sassanid gas a chemical weapon the Persians used against the Romans in wartime

Saturnalia an ancient Roman festival held in December in honor of the god Saturn, the Roman equivalent of Kronos

satyr a Greek forest god, part goat and part man

scusatemi Italian for excuse me

shadow-travel a form of transportation that allows creatures of the Underworld and children of Hades to use shadows to leap to any desired place on Earth or in the Underworld, although it makes the user extremely fatigued

Sibyl a prophetess

sica (siccae, pl.) a short, curved sword

Socrates a Greek philosopher (c. 470–399 BCE) who had a profound influence on Western thought

Stygian iron a magical metal forged in the River Styx, capable of absorbing the very essence of monsters and injuring mortals, gods, Titans, and giants; has a significant effect on ghosts and creatures from the Underworld

Styx a powerful water nymph; the eldest daughter of the sea Titan, Oceanus; goddess of the Underworld’s most important river; goddess of hatred; the River Styx is named after her

Sutro Tower a massive red-and-white transmission antenna in the San Francisco Bay Area where Harpocrates, the god of silence, was imprisoned by Commodus and Caligula

Tarquin Lucius Tarquinius Superbus was the seventh and final king of Rome, reigning from 534 to 509 BCE, when, after a popular uprising, the Roman Republic was established

Tartarus husband of Gaea; spirit of the abyss; father of the giants; the darkest pit in the Underworld, where monsters go when they are slain

taurus silvestre (tauri silvestres, pl.) a forest bull with an impenetrable hide; ancestral enemy of the troglodytes

Terpsichore Greek goddess of dance; one of the Nine Muses

terza rima a form of verse consisting of three-line stanzas in which the first and third lines rhyme and the middle line rhymes with the first and third lines of the following stanza

testudo a tortoise battle formation in which legionnaires put their shields together to form a barrier

Teumessian Fox a gigantic fox sent by the Olympians to prey upon the children of Thebes; it is destined never to be caught

Thalia the Muse of comedy

Three Graces the three charities: Beauty, Mirth, and Elegance; daughters of Zeus

Titans a race of powerful Greek deities, descendants of Gaea and Ouranos, that ruled during the Golden Age and were overthrown by a race of younger gods, the Olympians

triumvirate a political alliance formed by three parties

troglodytes a race of subterranean humanoids who eat lizards and fight bulls

Trojan War According to legend, the Trojan War was waged against the city of Troy by the Achaeans (Greeks) after Paris of Troy took Helen from her husband, Menelaus, king of Sparta

Trophonius demigod son of Apollo, designer of Apollo’s temple at Delphi, and spirit of the dark Oracle; he decapitated his half brother Agamethus to avoid discovery after their raid on King Hyrieus’s treasury

Troy a pre-Roman city situated in modern-day Turkey; site of the Trojan War

Underworld the kingdom of the dead, where souls go for eternity; ruled by Hades

ventus (venti, pl.) storm spirits

Venus the Roman goddess of love and beauty. Greek form: Aphrodite

Vnicornes Imperant Latin for Unicorns Rule

Vulcan the Roman god of fire, including volcanic, and of crafts and blacksmithing. Greek form: Hephaestus

Waystation a place of refuge for demigods, peaceful monsters, and Hunters of Artemis located above Union Station in Indianapolis, Indiana

Zeus the Greek god of the sky and the king of the gods. Roman form: Jupiter