The Games are the annual event where children from each district of Panem are forced to compete in a televised fight to the death.

The five factions in Divergent are Abnegation (the selfless), Amity (the peaceful), Candor (the honest), Dauntless (the brave), and Erudite (the intelligent).

The Maze is a vast, ever-changing labyrinth that the boys are trapped in. They must find a way to escape before they are killed by the Grievers, mechanical creatures that roam the maze.

The Surgery is the name of the surgery that teenagers undergo at the age of 16 to become "pretty" according to society's standards.

The Bureau of Genetic Welfare is the government agency that controls all aspects of society in Delirium, including marriage, reproduction, and even emotions.

The Mockingjay Rebellion is the rebellion that Katniss Everdeen inspires after she wins the Hunger Games for the second time.

Tris Prior joins the Amity faction after leaving Dauntless because she is tired of the violence and conflict that is prevalent in her former faction.

The Scorch is the name of the desert that the Gladers must cross in order to find a safe haven.

The Specials are the group of rebels who are fighting against the government in Pretties. They are led by Tally Youngblood, who was once a Pretty herself.

The Delirium is the name of the disease that is killing teenagers in Pandemonium. It is a mental illness that causes people to lose their memories and emotions.

The Battle of the Capitol is the final battle between the rebels and the Capitol in Mockingjay. It is a bloody and destructive battle that results in the overthrow of the Capitol and the establishment of a new government.

The Bureau of Genetic Welfare is the organization that is trying to control the Divergents in Allegiant. They believe that the Divergents are a threat to society and must be eliminated.

The Cure is the name of the final cure for the Flare in The Death Cure. It is a serum that is developed by Dr. Ava Paige and is able to stop the progression of the disease.

The Specials are the group of people who are born with special abilities in Extras. They are feared and persecuted by the government, which sees them as a threat to society.

The New World is the name of the new world that Lena and Alex create after the destruction of the old world in Requiem. It is a world where people are free to live their lives without fear or oppression.