The term "shipper" comes from supporting a ship. To ship something means a person wants two characters to get together and/or shows support for two characters already together. The term "ship" came from the X-Files fandom, when fanfics were written about Mulder and Scully. The fans then called themselves shippers. It quickly spread and is now the title a person gives themself if they believe two charcters should or will be together (The characters can be from anything: Books, Movies, Television, Video Games, and even Actors/Actresses). It is not limited to the couple actually happening, a person can ship something just because they enjoy the possibility of them getting together or even just because they think they would look good together.

A slang word derived from 'relationships' that generally means people who support certain relationships in fanfiction. It is a common joke to say that you "sail" on a certain ship. Most commonly identified with the Harry Potter fandom.

relationshipper; One who believes there is, was, should, and could be a relationship between 2 characters in a certain fandom.

a person who supports a relationship between two people, real or fictional.

A fan devoted to a paticular couple/pairing in a fandom. Usually fanatical.

Fanfics revolving around a certain relationship.

A shipper is singlehandedly one of the most annoying fans of television. They are obsessed with the notion that two characters of a TV show or movie should be or will be together. These particular type of fans have no interest in the more pertinent aspects of the show, just the romance of the characters they are shipping.

ABC's "LOST", is a perfect example of this annoying trend. The Jack/Kate/Sawyer love triangle have generated many shippers that call themselves "Jaters" (Kate/Jack relationship) or "Skaters" (Kate/Sawyer relationship). The shippers are occasionally mentioned and somewhat mocked by "LOST" producers Damon Lindelof and Carlton Cuse.

A "ship" usually gets its name by pairing the first letter of the male with the female's name, or vice versa. I.E. Brangelina.