The Tower of Nero

Erebos the Greek primordial god of darkness; a place of darkness between Earth and Hades

fasces a ceremonial ax wrapped in a bundle of thick wooden rods with its crescent-shaped blade projecting outward; the ultimate symbol of authority in ancient Rome; origin of the word fascism

Fates three female personifications of destiny. They control the thread of life for every living thing from birth to death.

faun a Roman forest god, part goat and part man

Fields of Punishment the section of the Underworld where people who were evil during their lives are sent to face eternal punishment for their crimes after death

Gaea the Greek earth goddess; wife of Ouranos; mother of the Titans, giants, Cyclopes, and other monsters

Ganymede a beautiful Trojan boy whom Zeus abducted to be cupbearer to the gods

Gaul the name that Romans gave to the Celts and their territories

Germanus (Germani, pl.) a bodyguard for the Roman Empire from the Gaulish and Germanic tribal people who settled to the west of the Rhine river

glámon the ancient Greek equivalent of dirty old man

Golden Fleece this hide from a gold-haired winged ram was a symbol of authority and kingship; it was guarded by a dragon and fire-breathing bulls; Jason was tasked with obtaining it, resulting in an epic quest. It now hangs on Thalia’s tree at Camp Half-Blood to help strengthen the magical borders.

Gray Sisters Tempest, Anger, and Wasp, a trio of old women who share a single eye and a single tooth and operate a taxi that serves the New York City area

Greek fire a magical, highly explosive, viscous green liquid used as a weapon; one of the most dangerous substances on earth

griffin a flying creature that is part lion, part eagle

Grove of Dodona the site of the oldest Greek Oracle, second only to Delphi in importance; the rustling of trees in the grove provided answers to priests and priestesses who journeyed to the site. The grove is located in Camp Half-Blood Forest and accessible only through the myrmekes’ lair.

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

Harpocrates the god of silence

harpy a winged female creature that snatches things

Hecate goddess of magic and crossroads

Helios the Titan god of the sun; son of the Titan Hyperion and the Titaness Theia

Hephaestus the Greek god of fire, including volcanic, and of crafts and blacksmithing; the son of Zeus and Hera, and married to Aphrodite. Roman form: Vulcan

Hera the Greek goddess of marriage; Zeus’s wife and sister; Apollo’s stepmother

Hermes Greek god of travelers; guide to spirits of the dead; god of communication. Roman form: Mercury

Herophile the Oracle of Erythraea; she spouts prophecies in the form of word puzzles

Hestia Greek goddess of the hearth

Hunters of Artemis a group of maidens loyal to Artemis and gifted with hunting skills and eternal youth as long as they reject men for life

Hyacinthus a Greek hero and Apollo’s lover, who died while trying to impress Apollo with his discus skills

Icarus the son of Daedalus, best known for flying too close to the sun while trying to escape the island of Crete by using metal-and-wax wings invented by his father; he died when he didn’t heed his father’s warnings

Imperial gold a rare metal deadly to monsters, consecrated at the Pantheon; its existence was a closely guarded secret of the emperors

Julius Caesar a Roman politician and general whose military accomplishments extended Rome’s territory and ultimately led to a civil war that enabled him to assume control of the government in 49 BCE. He was declared “dictator for life” and went on to institute social reforms that angered some powerful Romans. A group of senators conspired against him and assassinated him on March 15, 44 BCE.

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

karpos (karpoi, pl.) grain spirit; a child of Tartarus and Gaea

King Midas a ruler who was famous for being able to turn everything he touched into gold, an ability granted by Dionysus

Koronis one of Apollo’s girlfriends, who fell in love with another man. A white raven Apollo had left to guard her informed him of the affair. Apollo was so angry at the raven for failing to peck out the man’s eyes that he cursed the bird, scorching its feathers. Apollo sent his sister, Artemis, to kill Koronis, because he couldn’t bring himself to do it.

Kronos the Titan lord of time, evil, and the harvest. He is the youngest but boldest and most devious of Gaea’s children; he convinced several of his brothers to aid him in the murder of their father, Ouranos. He was also Percy Jackson’s primary opponent. Roman form: Saturn

Labyrinth an underground maze originally built on the island of Crete by the craftsman Daedalus to hold the Minotaur

Lar (Lares, pl.) Roman house gods

leontocephaline a being with the head of a lion and the body of a man entwined with a snake without a head or tail; created by Mithras, a Persian god, to protect his immortality

Leto mother of Artemis and Apollo with Zeus; goddess of motherhood

Lugus one of the major gods in ancient Celtic religion

Lupa the wolf goddess, guardian spirit of Rome

Mars the Roman god of war. Greek form: Ares

Marsyas a satyr who lost to Apollo after challenging him in a musical contest, which led to Marsyas being flayed alive

Meliai Greek nymphs of the ash tree, born of Gaea; they nurtured and raised Zeus in Crete

Mercury Roman god of travelers; guide to spirits of the dead; god of communication. Greek form: Hermes.

Minerva the Roman goddess of wisdom. Greek form: Athena

Minoans a Bronze Age civilization of Crete that flourished from c. 3000 to 1100 BCE; their name comes from King Minos

Minotaur the half-man, half-bull son of King Minos of Crete; the Minotaur was kept in the Labyrinth, where he killed people who were sent in; he was finally defeated by Theseus

Mist a magical force that prevents mortals from seeing gods, mythical creatures, and supernatural occurrences by replacing them with things the human mind can comprehend

Mithras a Persian god who was adopted by the Romans and became the god of warriors; he created the leontocephaline

Morpheus the Titan who put all the mortals in New York to sleep during the Battle of Manhattan

Mount Olympus home of the Twelve Olympians

naiad a female water spirit

nectar a drink of the gods that can heal demigods

Nero ruled as Roman Emperor from 54 to 58 CE; he had his mother and his first wife put to death; many believe he was responsible for setting a fire that gutted Rome, but he blamed the Christians, whom he burned on crosses; he built an extravagant new palace on the cleared land and lost support when construction expenses forced him to raise taxes; he committed suicide

New Rome both the valley in which Camp Jupiter is located and a city—a smaller, modern version of the imperial city—where Roman demigods can go to live in peace, study, and retire

Nine Muses goddesses who grant inspiration for and protect artistic creation and expression; daughters of Zeus and Mnemosyne; as children, they were taught by Apollo. Their names are: Clio, Euterpe, Thalia, Melpomene, Terpsichore, Erato, Polymnia, Ourania, and Calliope.

nymph a female deity who animates nature

omphalos Greek for navel of the world; the nickname for Delphi, a spring that whispered the future to those who would listen

Oracle of Delphi a speaker of the prophecies of Apollo

pandos (pandai, pl.) a man with gigantic ears, eight fingers and toes, and a body covered with hair that starts out white and turns black with age