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verb \ˈflī\

Definition of fly

flew play \ˈflü\ flown play \ˈflōn\ fly·ing

  1. intransitive verb
  2. 1 a :  to move in or pass through the air with wings b :  to move through the air or before the wind or through outer space c :  to float, wave, or soar in the air <flags flying at half-mast>

  3. 2 a :  to take flight :  flee b :  to fade and disappear :  vanish

  4. 3 a :  to move, pass, or spread quickly <rumors were flying> b :  to be moved with sudden extreme emotion <flew into a rage> c :  to seem to pass quickly <the time simply flew>

  5. 4 :  to become expended or dissipated rapidly

  6. 5 :  to operate or travel in an airplane or spacecraft

  7. 6 :  to work successfully :  win popular acceptance <knew … a pure human-rights approach would not fly — Charles Brydon>

  8. transitive verb
  9. 1 a :  to cause to fly, float, or hang in the air <flying a kite> b :  to operate (as a balloon, aircraft, rocket, or spacecraft) in flight c :  to journey over or through by flying

  10. 2 a :  to flee or escape from b :  avoid, shun

  11. 3 :  to transport by aircraft or spacecraft

fly at
  1. :  to assail suddenly and violently

fly blind
  1. :  to fly an airplane solely by instruments

fly high
  1. :  to be elated

fly in the face of or fly in the teeth of
  1. :  to stand or act forthrightly or brazenly in defiance or contradiction of

Origin of fly

Middle English flien, from Old English flēogan; akin to Old High German fliogan to fly and probably to Old English flōwan to flow

First Known Use: before 12th century




Definition of fly

plural flies

  1. 1 :  the action or process of flying :  flight

  2. 2 a :  a device consisting of two or more radial vanes capable of rotating on a spindle to act as a fan or to govern the speed of clockwork or very light machinery b :  flywheel

  3. 3 plural :  the space over a theater stage where scenery and equipment can be hung

  4. 4 :  something attached by one edge: as a :  a garment closing concealed by a fold of cloth extending over the fastener b (1) :  the length of an extended flag from its staff or support (2) :  the outer or loose end of a flag

  5. 5 :  a baseball hit high into the air

  6. 6 :  flyleaf

  7. 7 :  a sheet of material (as canvas) that is attachable to a tent for use as a double top or as a rooflike extension

  8. 8 :  a football pass pattern in which the receiver runs straight downfield

on the fly
  1. 1 :  in motion :  busy

  2. 2 :  while still in the air :  without the ball bouncing <the home run carried 450 feet on the fly>

  3. 3 :  in a hurry and often without preparation :  hastily, spontaneously <making decisions on the fly>

  4. 4 :  simultaneously with another task <software that handles formatting on the fly>

Before 12th Century

First Known Use of fly

before 12th century




Definition of fly


  1. intransitive verb
  2. :  to hit a fly in baseball


First Known Use of fly





Definition of fly

plural flies

  1. 1 :  a winged insect —usually used in combination <mayflies> <butterfly>

  2. 2 a :  any of a large order (Diptera) of winged or rarely wingless insects (as the housefly, mosquito, or gnat) that have the anterior wings functional, the posterior wings reduced to halteres, and segmented often headless, eyeless, and legless larvae — compare maggot b :  a large stout-bodied fly

  3. 3 :  a fishhook dressed (as with feathers or tinsel) to suggest an insect

fly in the ointment
  1. :  a detracting factor or element

Origin of fly

Middle English flie, from Old English flēoge; akin to Old High German flioga fly, Old English flēogan to fly

First Known Use: before 12th century

Other Insect Terms




Definition of fly

chiefly British

  1. :  keen, artful

Origin of fly

probably from 1fly

First Known Use: 1811


geographical name \ˈflī\

Definition of Fly

  1. river 650 miles (1046 kilometers) S New Guinea flowing SE into Gulf of Papua

Medical Dictionary


noun \ˈflī\

Medical Definition of fly

plural flies

  1. 1:  a winged insect—usually used in combination <emerging mayflies> <a large butterfly>

  2. 2a:  any dipteran fly—called also true fly, two-winged flyb:  a large and stout-bodied dipteran fly (as a horsefly)

Seen and Heard

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