flap

1 of 2

noun

ˈflap 

1

: something that is broad or flat and usually thin and flexible and that hangs loose or projects freely

opened the tent's flap and crawled in

: such as

a

: a piece on a garment that hangs free

The hat has flaps that can be pulled down to cover the ears.

b

: a part of a book jacket that folds under the book's cover

c

: a piece of tissue partly severed from its place of origin for use in surgical grafting

d

: an extended part forming the closure (as of an envelope or carton)

2

a

: the usually up and down or back and forth motion of something broad and usually flat and flexible (such as a wing or flag)

a flap of the seal's flippers

b

: the sound made by the motion of something broad and flexible

heard the flap of the sails in the wind

3

: a movable auxiliary airfoil usually attached to an airplane wing's trailing edge to increase lift or drag see airplane illustration

4

a

: a state of excitement or agitation : tizzy, uproar

—usually used in the phrase in a flap

When my aunts … did call unexpectedly … they always put my mother in a flap.

—Muriel Sparks

b

: something that generates an uproar

… when there was a flap abroad …

—Thomas Braden

5

: a consonant (such as the sound \d\ in ladder and \t\ in latter) characterized by a single rapid contact of the tongue or lower lip against another point in the mouth

called also tap

6

: a stroke with something broad : slap

7

obsolete : something broad and flat used for striking

flap

2 of 2

verb

flapped; flapping

intransitive verb

1

: to sway loosely usually with a noise of striking and especially when moved by wind

2

a

: to beat or pulsate wings or something suggesting wings

b

: to progress by flapping

c

: to flutter ineffectively

3

: to talk foolishly and persistently

transitive verb

1

: to beat with or as if with a flap

2

: to toss sharply : fling

3

: to move or cause to move in flaps

Synonyms of flap

Noun

• frenzy
• rampage

Verb

• flutter

Examples of flap in a Sentence

Noun

She opened the tent flap and crawled outside.

the inside flap of a book's cover

a loose flap of skin

Verb

The breeze flapped the sails.

The flag flapped in the breeze.

The bird's wings were flapping.

Recent Examples on the Web

Noun

The Baguette’s design includes a front flap, magnetic clasp, unlined internal compartment with a pocket and gold-finish metalware. —Julia Teti, Footwear News, 3 Nov. 2025

The jacket features pocket flaps shaped like Levi’s iconic arcuate, Trucker-style cuffs and waistband, and a back-cinch characteristic of Levi’s archival denim. —Angela Velasquez, Sourcing Journal, 30 Oct. 2025

Verb

Gauzy curtains that have blown into a tree are flapping in the wind. —Jane Arraf, NPR, 3 Nov. 2025

In the clip, Lecaillier cuts, tapes and shapes her materials until a wonderfully bonkers ostrich begins to take form — complete with flapping wings and a bobbing neck made from little more than determination and a sense of humor. —Ashley Vega, PEOPLE, 27 Oct. 2025

Word History

Etymology

Noun

Middle English flappe

First Known Use

Noun

14th century, in the meaning defined at sense 6

Verb

14th century, in the meaning defined at transitive sense 1

Phrases Containing flap

• in a flap
• mud flap

Rhymes for flap

• app
• cap
• chap
• clap
• crap
• frap
• gap
• hap
• lap
• nap
• nappe
• pap

Kids Definition

flap

1 of 2 noun

ˈflap 

1

: slap entry 1 sense 1

2

: a broad, limber, or flat piece that hangs loose (as on a pocket or envelope)

3

: the motion or sound of a flap

4

: a movable part of an airplane wing that is attached to the trailing edge of the wing and that is used to increase lift or drag

flap

2 of 2 verb

flapped; flapping

1

: slap entry 2 sense 1a

2

: to move or cause to move with a beating motion

flapping its wings

Medical Definition

flap

noun

ˈflap 

: a piece of tissue partly severed from its place of origin for use in surgical grafting