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to flatten out

to flatten out

5 3.4
To become flat and smooth after being uneven
  • phrasal verb
  • /ˈflætən aʊt/
translation icon : alisar
  • The aerial photographs show... that this... this gully runs back here about half a mile... then flattens out into a meadow.

Maybe it's sort of flattens out as you get to a certain speed.

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Examples

  • The colors of the room swam together, then flattened out.

    Fiction book (1996)
  • After rolling the dough, make sure to flatten out any air bubbles before baking.

  • You can see how it's starting to flatten out across the body.

  • But now it's starting to flatten out at the top.

  • "Look up ahead, I think it flattens out," he called back.

    Academic text (2002)
  • So they want to flatten out the distribution.

  • The land flattened out before them, and the jungle stretched away.

    Fiction book (1992)
  • The hills have flattened out to endless swells, with crests of sedimentary rock through which the highway is carved.

    Fiction book (2002)
  • She used a roller to flatten out the wrinkles in the fabric.

  • The technician needed to flatten out the surface before applying any paint.

Synonyms

to level
vsto flatten out
81 3.7

To make land or a building flat with the ground

describes becoming flat or smooth after uneven or rough conditions
to unfold
vsto flatten out
39 1.3

Open something that is folded so it becomes flat

is wider, applying to any flattening after roughness not only folds
to flatten
vsto flatten out
23 2.6

Make something flat and smooth by pressing it

is about becoming flat or smooth after being rough
to even
vsto flatten out
22 2.5

To make something level or smooth

focuses on becoming flat specifically after being uneven or rough
to even out
vsto flatten out
18 3.4

To make a surface, amount, or relationship level by removing differences

refers specifically to returning an uneven surface to flatness
to straighten out
vsto flatten out
11 2.9

To make something free of bends, twists, or knots

focuses specifically on making a surface flat after being uneven
to roll out
vsto flatten out
8 3.4

To make something flat by unrolling it or using a roller

is the general result of becoming flat regardless of method
to even up
vsto flatten out
3 5.3

To make the edges of a pile of papers level and straight

covers general flattening, not only edge or stack alignment
to grind down
vsto flatten out
2 6.1

Wear a surface away slowly by rubbing, or make someone very tired

is about becoming flat after roughness without stressing gradual abrasion
to smooth down
vsto flatten out
1 3.8

To make something less rough by pressing it flat or by calming people

is about physical flattening or smoothing after roughness rather than calming
to plane
vsto flatten out
1 7.5

To make a surface smooth by shaving thin layers of wood

is the general process of becoming flat without a specific tool focus
to level the ground
vsto flatten out
3.6

To make the ground flat for building or planting

applies more broadly to any object becoming flat after roughness
to smoothen
vsto flatten out
4.3

To make a surface flat and even by rubbing or polishing

centres on becoming flat or level after being uneven
to uncrumple
vsto flatten out
4.4

To make paper or cloth smooth again after it becomes wrinkled

is broader, covering becoming flat from any uneven or rough state
to unpucker
vsto flatten out
7.9

Smooth a wrinkled area of skin, fabric, or lips

covers flattening from many rough forms, not only puckers
to steamroll
vsto flatten out
4.9

Make a surface flat using a heavy roller machine

means becoming flat after roughness without implying a heavy machine

How Flat

to plane
1 7.5
to flatten out
5 3.4
to even out
18 3.4

Surface Forms

flatten out infinitive
flattened out past participle
flattening out present participle
flattens out third person singular

Morphology

flatten + out

The core meaning comes directly from 'flatten' (make flat) while the particle 'out' adds a sense of spreading, finishing, or making uniformly flat; together they yield 'make or become flat/smooth', which a B1 learner who knows both constituents can readily infer. This verb+particle composition is a common, predictable pattern in English (and has parallels in other languages), so the expression is compositional and transparent.

Etymology

Flatten out comes from the image of pressing something so the bumps disappear and it spreads out to lie flat. So it now means 'to become or make smooth or level' and, by extension, 'to stop changing quickly', as with paper, hills, or prices.