Output is the term denoting either an exit or changes which exit a system and which activate/modify a process. It is an abstract concept, used in the modeling, system(s) design and system(s) exploitation.

In control theory, the outputs of a system are what can be measured. Specifically, outputs are differentiated through many states.

In engineering the term output can refer to:

In equity theory, output is the benefits that an employee receives, including money, perquisites, power, status, fame or variety.

In human–computer interaction, output is information produced by the computer program and perceived by the user. The kinds of output the program makes, and the kinds of input the program accepts, define the user interface of the program. In this context, feedback and output are often used interchangeably. However, output tends to refer specifically to explicit output, something that is intentionally provided for the user, whereas feedback also encompasses byproducts of operation that happen to contain information (see low-key feedback).

Sander van Doorn (Dutch pronunciation: [ˈsɑn.dər vɑn ˈdoːrn]) (born Sander Ketelaars [Dutch pronunciation: [ˈsɑn.dər ˈkeː.tə.ˌlaːrs]] on 28 February 1979 in Eindhoven, Noord-Brabant, Netherlands) is a Dutch Trance music DJ and producer. He is listed at DJMag's top 100 djs list, debuting at #32 in 2006, then moving up to #13 in 2008, being #10 in 2009, down to #12 in 2010, and currently listed as #16 DJ in the world. Another dance music poll, TranceAddict TOP 250 shows Sander at #4 in their 2011 rankings.

Sander hosts Identity podcast, which is broadcast as a weekly radio show on Area channel of Sirius XM satellite radio. The show is broadcast every Friday at 8 pm ET and replays every Saturday at 5 pm ET and Wednesdays at 6 pm ET.

The first big achievement in his career was securing residencies at Judgement Sunday in Ibiza and at the Gallery in London. Sander has DJ'ed at many major clubs, parties and venues around the world. In June 2007 he presented one of Eddie Halliwell's shows on BBC Radio One. He also did an essential mix for BBC Radio One in June 2006, the same month he won 'Best New Producer' at the Trance Awards. His productions, both original work and remixes, in 2007-2008 have generally been well received in the electronic music industry. Notable artists he has done remixes for include Robbie Rivera, Matt Darey, Randy Katana, Mode Hookers (Steve Angello & Sebastian Ingrosso), Blank & Jones, TDR, Armin van Buuren.