[loop] 
| 1. | a portion of a cord, ribbon, etc., folded or doubled upon itself so as to leave an opening between the parts. |
| 2. | anything shaped more or less like a loop, as a line drawn on paper, a part of a letter, a part of a path, or a line of motion. |
| 3. | a curved piece or a ring of metal, wood, or the like, used for the insertion of something, as a handle, etc. |
| 4. | intrauterine device. |
| 5. | Aeronautics. a maneuver executed by an airplane in such a manner that the airplane describes a closed curve in a vertical plane. |
| 6. | a circular area at the end of a trolley line, railroad line, etc., where cars turn around. |
| 7. | an arm of a cloverleaf where traffic may turn off or onto a main road or highway. |
| 8. | Physics. the part of a vibrating string, column of air or other medium, etc., between two adjacent nodes. |
| 9. | Electricity. a closed electric or magnetic circuit. |
| 10. | Computers. the reiteration of a set of instructions in a routine or program. |
| 11. | a wire, usually of platinum, one end of which is curved to form a loop, used for transferring microorganisms from one medium to another. |
| 12. | a sand bar that encloses or nearly encloses a body of water. |
| 13. | Figure Skating. a school figure in which a skater traces a large half circle, a small oval within its arc, and another large half circle to complete the figure while remaining on the same skating edge. |
| 14. | the loop, a group or network of insiders or influential people; inner circle: to be out of the loop on policy decisions. |
| 15. | the Loop, the main business district of Chicago. |
| 16. | to form into a loop. |
| 17. | to make a loop in. |
| 18. | to enfold or encircle in or with something arranged in a loop. |
| 19. | to fasten by forming into a loop, or by means of something formed into a loop (often fol. by up): to loop up the new draperies. |
| 20. | to cause (a missile or projectile) to trace a looping or looplike trajectory through the air: to loop a grenade into the building. |
| 21. | to fly (an airplane) in a loop or series of loops. |
| 22. | to construct a closed electric or magnetic circuit. |
| 23. | Movies. to complete by means of looping: We still have to loop the final scenes. |
| 24. | to make or form a loop: The river loops around the two counties. |
| 25. | to move by forming loops, as a measuringworm. |
| 26. | to trace a looping or looplike path through the air: The fly ball looped high in the air. |
| 27. | to perform a loop or series of loops in an airplane. |
| 28. | Movies. to record dialogue, sound effects, etc., onto an existing film track or soundtrack. |
| 29. | throw or knock for a loop, to astonish or upset: Her quitting the project really threw me for a loop. |
| loop 1 (lōōp) n.
v. tr.
[Middle English loupe, probably from Middle Irish lúb (perhaps influenced by Middle English lep, basket).] |
loop (l&oomacr;p)
n.
A curve or bend in a cord or other cylindrical body, forming an oval or circular ring.
knock for a loop
Also, throw for a loop; knock down or over with a feather; . Overcome with surprise or astonishment, as in The news of his death knocked me for a loop, or Being fired without any warning threw me for a loop, or Jane was knocked sideways when she found out she won. The first two of these hyperbolic colloquial usages, dating from the first half of the 1900s, allude to the comic-strip image of a person pushed hard enough to roll over in the shape of a loop. The third hyperbolic term, often put as You could have knocked me down with a feather, intimating that something so light as a feather could knock one down, dates from the early 1800s; the fourth was first recorded in 1925.