First Twin and Second Twin, the twin lost boys in J.M. Barrie's Peter Pan

Multiple births, while not necessarily twins, are sometimes referred to as "multiple twins".

Conjoined twins, or Siamese

Twin, a standard bed, mattress, or sheet size

Town twinning, two distant cities that agree to partner each other, for various reasons

Parasitic twin, a very rare condition caused by a variety of circumstances

Twin (computing), a Text WINdows computer interface

TWIN (music producer),a music production Team

Twins, a photobook by Steven Underhill

In biology, Twins are two or more siblings which gestated and were born together. Types of biological twins include:

Twin can also refer to a doppelgänger or clone.

Twin boundary, where two crystallites which share atoms at repeated intervals and have only a minor difference in orientation meet at

Twin cities, two towns or cities that are geographically close to each other, and often referred to collectively. The term is most often used to describe the Minneapolis-St. Paul metropolitan area in Minnesota, United States. Other examples include the Twin Ports of Duluth, Minnesota and Superior, Wisconsin, United States.

Twin prime, a prime number that differs from another prime number by two

Twin Towers are any of a number of matching structures, most notably the former World Trade Center in New York City

Minnesota Twins of Major League Baseball, which take their name from the Twin Cities of Minneapolis and St. Paul

Twin (mythology), a very common theme in mythology

Twin paradox, a thought experiment in special relativity

Twins (album), the name of Twins self-titled album

Twins (band), a Hong Kong-based Cantopop musical group

Twins (film), a 1988 comedy film starring Arnold Schwarzenegger and Danny DeVito

Twins (1925 film), a 1925 film starring Stan Laurel

Twins (pornographic film), the name of two gay pornographic movies, one starring the O'Brien Twins, Christy twins and Karisdtadt Twins, and the other starring the Oddyssey Twins

Twins (The Matrix), characters from The Matrix Reloaded

Twins (TV series), a sitcom that debuted on The WB Television Network in September 2005

Twins, a song by Manitoba from their 2003 album, Up in Flames

TWINS (Knock Out), a song by Super Junior from their 2005 album, Super Junior 05