From Middle English loupe, earlier lowp-knot, of gmq origin, from Old Norse hlaup, used in the sense of a "running knot", from hlaupa ("to leap"), ultimately from Proto-Germanic *hlaupaną.

• IPA: /luːp/

loop (plural loops)

1. A length of thread, line or rope that is doubled over to make an opening.
2. The opening so formed.
3. A shape produced by a curve that bends around and crosses itself.

   Arches, loops, and whorls are patterns found in fingerprints.

4. A ring road or beltway.
5. An endless strip of tape or film allowing continuous repetition.
6. A complete circuit for an electric current.
7. (programming) A programmed sequence of instructions that is repeated until or while a particular condition is satisfied.
8. (graph theory) An edge that begins and ends on the same vertex.
9. (topology) A path that starts and ends at the same point.
10. (transportation) A bus or rail route, walking route, etc. that starts and ends at the same point.
11. (rail) A place at a terminus where trains or trams can turn round and go back the other way without having to reverse; a balloon loop, turning loop, or reversing loop.
12. (algebra) A quasigroup with an identity element.
13. A loop-shaped intrauterine device.
14. An aerobatic maneuver in which an aircraft flies a circular path in a vertical plane.
15. A small, narrow opening; a loophole.
    • c. 1597 (date written), William Shakespeare, “The First Part of Henry the Fourth, […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC ↗, [Act IV, scene i]:

      And stop all sight-holes, every loop from whence / The eye of Reason may pry in upon us.

16. Alternative form of loup
17. (biochemistry) A flexible region in a protein's secondary structure.
18. (North America, dated, sports) A sports league
    • 1963 September 27, “Italias Vie In Bayonne On Sunday ↗”, in The Jersey Journal, page 17:

      Arellano formerly cavorted for the Galicias in the fast-paced National-American Soccer loop.

• French: boucle
• German: Schlaufe
• Portuguese: laço
• Russian: пе́тля́
• Spanish: lazo, lazada, gaza (nautical), recodo

• French: boucle
• German: Schlaufe, Schleife
• Italian: passante
• Portuguese: laço
• Russian: пе́тля́
• Spanish: lazo, recodo, vuelta, círculo, bucle

• German: Endlosschleife
• Italian: riccio
• Portuguese: fita
• Russian: пе́тля́
• Spanish: rizo, círculo, bucle infinito, cinta infinita

• French: circuit fermé
• German: Stromkreis, geschlossener Stromkreis
• Italian: anello
• Portuguese: circuito
• Russian: цепь
• Spanish: circuito cerrado

• French: boucle
• German: Schleife
• Italian: blocco iterativo, iterazione , ciclo
• Portuguese: ciclo, laço, loop
• Russian: цикл
• Spanish: ciclo, bucle

• French: boucle
• German: Schlaufe
• Spanish: lazo

• Spanish: lazo

• French: boucle
• German: Rundweg, Ring, Ringstraße, Gürtel
• Spanish: vuelta, anillo vial, anillo, ronda, ronda, circunvalación

• German: Loop
• Spanish: bucle

• Italian: spirale
• Russian: (внутрима́точная противозача́точная) спира́ль

• French: boucle
• German: Looping
• Italian: cerchio della morte, giro della morte
• Portuguese: looping, loop
• Russian: мёртвая пе́тля́
• Spanish: looping, rizo

loop (loops, present participle looping; simple past and past participle looped)

1. (transitive) To form something into a loop.
2. (transitive) To fasten or encircle something with a loop.
3. (transitive) To fly an aircraft in a loop.
4. (transitive) To move something in a loop.
5. (transitive) To join electrical components to complete a circuit.
6. (transitive) To duplicate the route of a pipeline.
7. (transitive) To create an error in a computer program so that it runs in an endless loop and the computer freezes up.
8. (intransitive) To form a loop.
9. (intransitive) To move in a loop.

   The program loops until the user presses a key.

10. To place in a loop.
11. (education, ambitransitive) To have the teacher progress through multiple school years with the same students.

1. Surname.
2. (Melbourne, informal, in the singular) The City Loop.

   Does this train go through the Loop?

loop

1. Acronym of loss of offsite power