absurdus out of place, discordant

Achilles the mightiest of the Greek demigods who fought in the Trojan War

Aesculapius the Roman god of medicine and healing

Alcyoneus the eldest of the giants born to Gaea, destined to fight Pluto

Amazons a nation of all-female warriors

Anaklusmos Riptide. The name of Percy Jackson’s sword.

argentum silver

Argonauts a band of Greek heroes who accompanied Jason on his quest to find the Golden Fleece. Their name comes from their ship, the Argo, which was named after its builder, Argus.

augury a sign of something coming, an omen; the practice of divining the future

aurae invisible wind spirits

aurum gold

basilisk snake, literally “little crown”

Bellerophon a Greek demigod, son of Poseidon, who defeated monsters while riding on Pegasus

Bellona the Roman goddess of war

Byzantium the eastern empire that lasted another 1,000 years after Rome fell, under Greek influence

Celestial bronze a rare metal deadly to monsters

Centaur a race of creatures that is half human, half horse

centurion an officer of the Roman army

Cerberus the three-headed dog that guards the gates of the Underworld

Ceres the Roman goddess of agriculture

Charon the ferryman of Hades who carries souls of the newly deceased across the rivers Styx and Acheron, which divide the world of the living from the world of the dead

cognomen third name

cohort a Roman military unit

Cyclops a member of a primordial race of giants (Cyclopes, pl.), each with a single eye in the middle of his or her forehead

denarius (denarii, pl.) the most common coin in the Roman currency system

drachma the silver coin of ancient Greece

Elysium the final resting place of the souls of the heroic and the virtuous in the Underworld

Erebos a place of darkness between Earth and Hades

faun a Roman forest god, part goat and part man. Greek form: satyr

Fields of Asphodel the section of the Underworld where the souls of people who lived lives of equal good and evil rest

Fields of Punishment the section of the Underworld where evil souls are eternally tortured

Fortuna the Roman goddess of fortune and good luck

Fulminata armed with lightning. A Roman legion under Julius Caesar whose emblem was a lightning bolt (fulmen).

Gaea the earth goddess; mother of Titans, giants, Cyclopes, and other monsters. Known to the Romans as Terra

Gegenes earthborn monsters

gladius a short sword

gorgons three monstrous sisters (Stheno, Euryale, and Medusa) who have hair of living, venomous snakes; Medusa’s eyes can turn the beholder to stone

graecus Greek; enemy; outsider

greaves shin armor

gris-gris a voodoo amulet that protects from evil or brings luck

harpy a winged female creature that snatches things

Hercules the Roman equivalent of Heracles; the son of Jupiter and Alcmene, who was born with great strength

Hyperboreans peaceful northern giants

ichor the golden blood of immortals

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

Iris the rainbow goddess

Juno Roman goddess of women, marriage, and fertility; sister and wife of Jupiter; mother of Mars. Greek form: Hera

Jupiter Roman king of the gods; also called Jupiter Optimus Maximus (the best and the greatest). Greek form: Zeus

karpoi grain spirits

Laistrygonians tall cannibals from the north, possibly the source of the Sasquatch legend

Lar house god, ancestral spirit (Lares, pl.)

legion the major unit of the Roman army, consisting of infantry and cavalry troops

legionnaire a member of a legion

Liberalia a Roman festival that celebrated a boy’s rite of passage into manhood

Lupa the sacred Roman she-wolf that nursed the foundling twins Romulus and Remus

Mars the Roman god of war; also called Mars Ultor. Patron of the empire; divine father of Romulus and Remus. Greek form: Ares

Minerva Roman goddess of wisdom. Greek form: Athena

Mist magic force that disguises things from mortals

Mount Othrys the base of the Titans during the ten-year war with the Olympian gods; Saturn’s headquarters

muster formal military inspection

nebulae cloud nymphs

Neptune the Roman god of the sea. Greek form: Poseidon

Otrera first Amazon queen, daughter of Ares pallium a cloak or mantle worn by the Romans Pantheon a temple to all the gods of Ancient Rome

Penthesilea a queen of the Amazons; daughter of Ares and Otrera, another Amazon queen

Periclymenus a Greek prince of Pylos and a son of Poseidon, who granted him the ability to shape-shift. He was renowned for his strength and participated in the voyage of the Argonauts.

Phineas a son of Poseidon, who had the gift of prophecy. When he revealed too much of the plans of the gods, Zeus punished him by blinding him.

pilum a Roman spear

Pluto the Roman god of death and riches. Greek equivalent: Hades

Polybotes the giant son of Gaea, the Earth Mother

praetor an elected Roman magistrate and commander of the army

Priam the king of Troy during the Trojan War principia the headquarters of a Roman camp probatio testing period for a new recruit in a legion pugio a Roman dagger

Queen Hippolyta’s belt Hippolyta wore a golden waist belt, a gift from her

father, Ares, that signified her Amazonian queenship and also gave her strength.

retiarius Roman gladiator who fought with a net and trident

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

Romulus and Remus the twin sons of Mars and the priestess Rhea Silvia who were thrown into the River Tiber by their human father, Amulius. They were rescued and raised by a she-wolf and, upon reaching adulthood, founded Rome.

Saturn the Roman god of agriculture, the son of Uranus and Gaea and the father of Jupiter. Greek equivalent:Kronos

scorpion ballista a Roman missile siege weapon that launched a large projectile at a distant target

Senatus Populusque Romanus (SPQR) “The Senate and People of Rome”; refers to the government of the Roman Republic and is used as an official emblem of Rome

shades spirits

Sibylline Books a collection of prophecies in rhyme written in Greek.

Tarquinius Superbus, a king of Rome, bought them from a prophetess named Sibyl and consulted them in times of great danger.

spartus a skeleton warrior

spatha a cavalry sword

Stygian iron like Celestial bronze and Imperial gold, a magical metal capable of killing monsters

Tartarus husband of Gaea; spirit of the abyss; father of the giants; also the lowest region of the world

Terminus the Roman god of boundaries and landmarks

Thanatos the Greek god of death. Roman equivalent: Letus

Tiber River the third-longest river in Italy. Rome was founded on its banks.

In ancient Rome, executed criminals were thrown into the river.

trireme a type of warship

triumph a ceremonial procession for Roman generals and their troops in celebration of a great military victory

Trojan War the war that was waged against the city of Troy by the Greeks after Paris of Troy took Helen from her husband, Menelaus, the king of Sparta. It started with a quarrel between the goddesses Athena, Hera, and Aphrodite.

Read Next Book –The Mark of Athena