Loop

A loop is generally something that closes back on itself such as a circle or ring.

Science and technology

• Loop (algebra), a quasigroup with an identity element
• Loop (graph theory), an edge that begins and ends on the same vertex
• Loop (topology), a path that starts and ends at the same point
• Program loop (computers), a sequence of commands that is executed repeatedly
• Wilson loop (physics), a closed path integral of the gauge field
• Loop (electricity), a closed circuit
• Loop (knot), one of the fundamental structures used to tie knots
• Loop (telecommunication), sending a signal on a channel and receiving it back at the sending terminal
• Local loop (telecommunication), the link connecting the customer to the carrier
• Loop antenna, a radio antenna composed of one or more turns of conductor
• Loop device (Unix), a device node that allows a file to be mounted on a directory

Movement and transportation

• Loop jump (figure skating), a jump that takes off from a back outside edge and lands on the same edge
• Loop (figure skating), one of the compulsory figures
• Loop (aircraft), an aerobatic maneuver
• Loop (roller coaster), the most basic of roller coaster inversions
• Loop (rail), one of several looping track configurations
• Loop route (road transport); see also Beltway.
• Loop ramp (road transport), an element of a cloverleaf interchange allowing left turns via a 270° right turn

Creative works

• Loop (novel), a sequel to the Japanese horror novel Ring
• Loop (band), a Shoegazing band
• Music loop, a finite element of sound which is repeated by technical means
• To "loop" is a term used in audio post production where an actor re-records his/her voice in a studio setting. This term is currently often replaced with the term "ADR" or Automated Dialogue Replacement. This is used when the original audio that was recorded on set was poor/damaged/lost etc. The term "loop" itself refers, as much of the film industry terminology does, to the old days where the actor was shown a continual film loop of the scene he/she was recording so that they would be able to synchronize their voice with the performance that was shot at an earlier date. Now, of course, looping or ADR is recorded using computer software.
• In animation, a loop is a sequence of drawings repeated over and over.
• In a movie projector, the loop refers to the slack portion of the film around the projector lens.
• A loop is industry vernacular for short pornographic films, many times without sound. Most are cheaply made and of poor quality. Before the advent of home video, such films were typically viewed by a single person in a booth, and the film was "looped" so that it could be played repeatedly when activated by a coin payment slot or similar device.

Other

• The Loop, the downtown neighborhood of Chicago, Illinois bounded by an elevated railway in the shape of a loop
• Loop (education), to advance an elementary school teacher with his or her class
• Louisiana Offshore Oil Port
• Loupe, a small magnifying glass used by jewelers, watchmakers, and other precision craftsmen