An episode is a part of a dramatic work such as a serial television or radio program. An episode is a part of a sequence of a body of work, akin to a chapter of a book. The term sometimes applies to works based on other forms of mass media as well, as in Star Wars. Episodes of news programs are also known as editions.

Episodes which end in the middle of a climatic moment are often called cliffhangers, after the name used for early movie serials. Such episodes can be nearly daily occurrences in soap operas and are frequently used in season finales of many prime time shows.

Episodes can be part of a larger story arc stretched out over a time period covering one or more seasons, or even an entire series run. This is true for some science fiction series such as Babylon 5, Stargate SG-1, Star Trek and Doctor Who.

Shows usually have numbers or codes (aka, Production codes/numbers) for each episode. The X-Files, for example, assigned a code in the format "sXnn", with 's' identifying the season number and 'nn' being a two-digit number for each show, starting with '01'. Some programs, such as The Simpsons, use numbering systems that are hard for anyone outside the production company to understand.

Many talk shows do not give episodes titles. However, some talk shows have given episodes titles, such as The Jerry Springer Show and The Steve Wilkos Show.

Some series often give episodes their own titles which usually refer to the content of the episode, giving both producers and fans a simple identification, these will usually have a pattern such as being a pun on a known item (such as a phrase or title of a of some other media) or follow some naming convention of the series:

• Most episodes of The Simpsons, and all of the nineteenth season parodies popular culture (ex. "Papa Don't Preach" is changed to "Papa Don't Leech").
• All episodes of Hannah Montana parody famous song titles, like "I Am Woman, Hear Me Roar" is changed to "I Am Hannah, Hear Me Croak".
• All episodes of Seinfeld, with the exception of Male Unbonding, start with "The".
• All episodes of The O.C. start with "The".
• Episode titles of Monk always begin with "Mr. Monk "
• Episode titles of Friends almost always begin with "The one with" or "The one where"
• Episode titles of Scrubs usually begin with "My" as they are narrated by J.D., the main character. They are sometimes called "His Story" or "Her Story", followed by a roman numeral when narrated by another character.
• Later seasons of Diagnosis: Murder usually included "Murder" in their titles.
• All episodes of Ed, Edd n' Eddy have the word "Ed" in their titles.
• Starting with season 2, each episode of Degrassi:The Next Generation is named after an 80's song.
• Each episode of Grey's Anatomy and Instant Star is named after a popular song.
• All episodes of Private Practice (Season 1) begin with "In Which".
• All episodes of the Nickelodeon show iCarly begin with "i".
• All episodes of the sitcom Still Standing begin with the word "Still".
• Most episodes of Desperate Housewives are named after songs related to Stephen Sondheim.
• All episodes of Chuck are named "Chuck versus the ...."
• In the sitcom That '70s Show, for Seasons 5–8, episodes were titled after song names from various 1970s-era rock bands. All fifth season episodes are named after songs by Led Zeppelin, all sixth season titles are The Who songs, all seventh season titles are The Rolling Stones songs and, except for the finale, all eighth season titles are Queen songs.
• Each episode of the teen drama One Tree Hill is named after an emo, rock, punk, or indie song or album.
• All episodes of the short-lived sitcom Love, Inc were named after a popular sitcome.
• All episodes of the teen drama The Best Years were named after movies.
• All episodes of The Days and Nights of Molly Dodd begin with "Here's" or "Here".