Thin vs. Flat — What's the Difference?

With opposite surfaces or sides that are close or relatively close together

Having a level surface; without raised areas or indentations

Having little, or too little, flesh or fat on the body

Lacking emotion; dull and lifeless

Having few parts or members relative to the area covered or filled; sparse

(of a sparkling drink) having lost its effervescence

(of a liquid substance) not containing much solid; flowing freely

(of a fee, wage, or price) the same in all cases, not varying with changed conditions or in particular cases

Lacking substance or quality; weak or inadequate

(of musical sound) below true or normal pitch.

With little thickness or depth

Relating to flat racing

Make or become less dense, crowded, or numerous

In or to a horizontal position

Make or become smaller in thickness

Completely; absolutely

Hit (a ball) above its centre.

Below the true or normal pitch of musical sound

Relatively small in extent from one surface to the opposite, usually in the smallest solid dimension

The flat part of something

Not great in diameter or cross section; fine

An upright section of stage scenery mounted on a movable frame.

Having little bodily flesh or fat; lean or slender.

A flat tyre

Not dense or concentrated; sparse

Flat racing.

More rarefied than normal

A musical note lowered a semitone below natural pitch.

Flowing with relative ease; not viscous

A set of rooms forming an individual residence, typically on one floor and within a larger building containing a number of such residences.

Watery

Lower (a note) by a semitone

Sparsely supplied or provided; scanty

Make flat; flatten

Having a low number of transactions

Live in or share a flat

Lacking force or substance; flimsy

Having a smooth, even surface

Lacking resonance or fullness; tinny

Having a relatively broad level surface in relation to thickness or depth

Lacking radiance or intensity

Being in horizontal position; lying down

Not having enough photographic density or contrast to make satisfactory prints. Used of a negative.

Being without slope or curvature

In a thin manner

Having a low heel or no heel

So as to be thin

Free of qualification; absolute

To make or become thin or thinner.

Fixed; unvarying

Having little thickness or extent from one surface to its opposite.

Lacking interest or excitement; dull

Very narrow in all diameters; having a cross section that is small in all directions.

Lacking in flavor

Having little body fat or flesh; slim; slender; lean; gaunt.

Having lost effervescence or sparkle

Of low viscosity or low specific gravity.

Deflated. Used of a tire.

Scarce; not close, crowded, or numerous; not filling the space.

Electrically discharged. Used of a storage battery.

(golf) Describing a poorly played golf shot where the ball is struck by the bottom part of the club head. See fat, shank, toe.

Of or relating to a horizontal line that displays no ups or downs and signifies the absence of physiological activity

Lacking body or volume; small; feeble; not full.

Of or relating to a hierarchy with relatively few tiers or levels

Slight; small; slender; flimsy; superficial; inadequate; not sufficient for a covering.

Commercially inactive; sluggish

(aviation) Of a route: relatively little used.

Unmodulated; monotonous

Poor; scanty; without money or success.

Lacking variety in tint or shading; uniform

(philately) A loss or tearing of paper from the back of a stamp, although not sufficient to create a complete hole.

Not glossy; matte

Any food produced or served in thin slices.

Being below the correct pitch.

(transitive) To make thin or thinner.

Being one half step lower than the corresponding natural key

(intransitive) To become thin or thinner.

Designating the vowel a as pronounced in bad or cat.

To dilute.

(Nautical) Taut. Used of a sail.

To remove some plants or parts of plants in order to improve the growth of what remains.

(Informal) Having small breasts.

Not thickly or closely; in a scattered state.

Level with the ground; horizontally.

Having little thickness or extent from one surface to its opposite; as, a thin plate of metal; thin paper; a thin board; a thin covering.

On or up against a flat surface; at full length.

Rare; not dense or thick; - applied to fluids or soft mixtures; as, thin blood; thin broth; thin air.

So as to be flat.

Not close; not crowded; not filling the space; not having the individuals of which the thing is composed in a close or compact state; hence, not abundant; as, the trees of a forest are thin; the corn or grass is thin.

Directly; completely

Not full or well grown; wanting in plumpness.

Exactly; precisely

Not stout; slim; slender; lean; gaunt; as, a person becomes thin by disease.

(Music) Below the intended pitch.

Wanting in body or volume; small; feeble; not full.

(Business) Without interest charge.

Slight; small; slender; flimsy; wanting substance or depth or force; superficial; inadequate; not sufficient for a covering; as, a thin disguise.

A flat surface or part.

Not thickly or closely; in a seattered state; as, seed sown thin.

Often flats A stretch of level ground

To make thin (in any of the senses of the adjective).

A shallow frame or box for seeds or seedlings.

To grow or become thin; - used with some adverbs, as out, away, etc.; as, geological strata thin out, i. e., gradually diminish in thickness until they disappear.

A movable section of stage scenery, usually consisting of a wooden frame and a decorated panel of wood or cloth.

Lose thickness; become thin or thinner

A flatcar.

Make thin or thinner;

A deflated tire.

Lessen the strength or flavor of a solution or mixture;

A shoe with a flat heel.

Take off weight

A large flat piece of mail.

Of relatively small extent from one surface to the opposite or in cross section;

A horse that competes in a flat race. Also called runner.

Lacking excess flesh;

A sign (♭) used to indicate that a note is to be lowered by a semitone.

Very narrow;

A note that is lowered a semitone.

Having little substance or significance;

(Football) The area of the field to either side of an offensive formation.

Not dense;

An apartment on one floor of a building.

Relatively thin in consistency or low in density; not viscous;

(Archaic) A story in a house.

(of sound) lacking resonance or volume;

To make flat; flatten.

Lacking spirit or sincere effort;

(Music) To lower (a note) a semitone.

Without viscosity;

To sing or play below the proper pitch.

Having no variations in height.

In a horizontal line or plane; not sloping.

Smooth; having no protrusions, indentations or other surface irregularities, or relatively so.

(slang) Having small or invisible breasts and/or buttocks.

Without variation in level, quantity, value, tone etc.

At a consistently depressed level; consistently lacklustre.

Of fees, fares etc., fixed; unvarying.

Without variations in pitch.

(of colours) Without variation in tone or hue (uniform), and dull (not glossy).

(figurative) Lacking liveliness or action; depressed; uninteresting; dull and boring.

Lacking in depth, substance, or believability; underdeveloped; one-dimensional.

Lowered by one semitone.

(music) Of a note or voice, lower in pitch than it should be.

Absolute; downright; peremptory.

(of a tire or other inflated object) Deflated, especially because of a puncture.

(of a carbonated drink) With all or most of its carbon dioxide having come out of solution so that the drink no longer fizzes or contains any bubbles.

(wine) Lacking acidity without being sweet.

(of a battery) Unable to emit power; dead.

Without spin; spinless.

Sonant; vocal, as distinguished from a sharp (non-sonant) consonant.

(grammar) Not having an inflectional ending or sign, such as a noun used as an adjective, or an adjective as an adverb, without the addition of a formative suffix; or an infinitive without the sign "to".

Having a head at a very obtuse angle to the shaft.

Flattening at the ends.

(of measurements of time) Exact.

So as to be flat.

Bluntly.

(of accurately measured timings) Exactly, precisely.

Used to emphasize the smallness of the measurement.

Completely.

Directly; flatly.

Without allowance for accrued interest.

An area of level ground (sometimes covered with water).

(in the phrase 'the flat') Level ground in general.

Level horse-racing ground, as contrasted with courses incorporating jumps, or the racing done on such ground.

The area in the centre of a racecourse.

(music) A note played a semitone lower than a natural, denoted by the symbol ♭ placed after the letter representing the note (e.g., B♭) or in front of the note symbol (e.g. ♭♪).

A flat tyre/flat tire.

(in the plural) A type of ladies' shoe with a very low heel.

(in the plural) A type of flat-soled running shoe without spikes.

(painting) A thin, broad brush used in oil and watercolour painting.

The flat part of something:

(swordfighting) The flat side of a blade, as opposed to the sharp edge.

The palm of the hand, with the adjacent part of the fingers.

A wide, shallow container or pallet.

(mail) A large mail piece measuring at least 8 1/2 by 11 inches, such as catalogs, magazines, and unfolded paper enclosed in large envelopes.

A railroad car without a roof, and whose body is a platform without sides; a platform car or flatcar.

A flat-bottomed boat, without keel, and of small draught.

(geometry) A subset of n-dimensional space that is congruent to a Euclidean space of lower dimension.

A straw hat, broad-brimmed and low-crowned.

A flat sheet for use on a bed.

(publishing) A flat, glossy children's book with few pages.

A platform on a wheel, upon which emblematic designs etc. are carried in processions.

(mining) A horizontal vein or ore deposit auxiliary to a main vein; also, any horizontal portion of a vein not elsewhere horizontal.

(technical, theatre, stagecraft) A rectangular wooden structure covered with masonite, lauan, or muslin, often produced in standard modules, that is used to build wall surfaces on stage. Flats can be painted and outfitted with doors and/or windows to depict a building or other part of a scene. It's a hard-surfaced alternative to a backcloth orbackdrop.

(entomology) Any of various hesperiid butterflies that spread their wings open when they land.

(historical) An early kind of toy soldier having a flat design.

(obsolete) A dull fellow; a simpleton.

(optics) A flat (i.e. plane) mirror

A cheater's die with the edges shaved to make certain rolls more likely.

An apartment, usually on one level and usually consisting of more than one room.

(poker slang) To make a flat call; to call without raising.

(intransitive) To become flat or flattened; to sink or fall to an even surface.

To fall from the pitch.

To depress in tone, as a musical note; especially, to lower in pitch by half a tone.

To make flat; to flatten; to level.

To render dull, insipid, or spiritless; to depress.

To beat or strike; pound

(transitive) To dash or throw

(intransitive) To dash, rush

Having an even and horizontal surface, or nearly so, without prominences or depressions; level without inclination; plane.

Lying at full length, or spread out, upon the ground; level with the ground or earth; prostrate; as, to lie flat on the ground; hence, fallen; laid low; ruined; destroyed.

Wanting relief; destitute of variety; without points of prominence and striking interest.

Tasteless; stale; vapid; insipid; dead; as, fruit or drink flat to the taste.

Unanimated; dull; uninteresting; without point or spirit; monotonous; as, a flat speech or composition.

Lacking liveliness of commercial exchange and dealings; depressed; dull; as, the market is flat.

Clear; unmistakable; peremptory; absolute; positive; downright.

Below the true pitch; hence, as applied to intervals, minor, or lower by a half step; as, a flat seventh; A flat.

Sonant; vocal; - applied to any one of the sonant or vocal consonants, as distinguished from a nonsonant (or sharp) consonant.

Having a head at a very obtuse angle to the shaft; - said of a club.

Not having an inflectional ending or sign, as a noun used as an adjective, or an adjective as an adverb, without the addition of a formative suffix, or an infinitive without the sign to. Many flat adverbs, as in run fast, buy cheap, are from AS. adverbs in -ë, the loss of this ending having made them like the adjectives. Some having forms in ly, such as exceeding, wonderful, true, are now archaic.

Flattening at the ends; - said of certain fruits.

In a flat manner; directly; flatly.

Without allowance for accrued interest.

A level surface, without elevation, relief, or prominences; an extended plain; specifically, in the United States, a level tract along the along the banks of a river; as, the Mohawk Flats.

A level tract lying at little depth below the surface of water, or alternately covered and left bare by the tide; a shoal; a shallow; a strand.

Something broad and flat in form

The flat part, or side, of anything; as, the broad side of a blade, as distinguished from its edge.

A floor, loft, or story in a building;

A horizontal vein or ore deposit auxiliary to a main vein; also, any horizontal portion of a vein not elsewhere horizontal.

A dull fellow; a simpleton; a numskull.

A character [$] before a note, indicating a tone which is a half step or semitone lower.

A homaloid space or extension.

To make flat; to flatten; to level.

To render dull, insipid, or spiritless; to depress.

To depress in tone, as a musical note; especially, to lower in pitch by half a tone.

To become flat, or flattened; to sink or fall to an even surface.

To fall form the pitch.

A level tract of land

A shallow box in which seedlings are started

A musical notation indicating one half step lower than the note named

Freight car without permanent sides or roof

A deflated pneumatic tire

Scenery consisting of a wooden frame covered with painted canvas; part of a stage setting

A suite of rooms usually on one floor of an apartment house

Having a horizontal surface in which no part is higher or lower than another;

Having no depth or thickness

Not modified or restricted by reservations;

Stretched out and lying at full length along the ground;

Lacking contrast or shading between tones

Lowered in pitch by one chromatic semitone;

Flattened laterally along the whole length (e.g., certain leafstalks or flatfishes)

Lacking taste or flavor or tang;

Lacking stimulating characteristics; uninteresting;

Having lost effervescence;

Not increasing as the amount taxed increases

Not made with leavening;

Parallel to the ground;

Without pleats

Lacking the expected range or depth; not designed to give an illusion or depth;

(of a tire) completely or partially deflated

Not reflecting light; not glossy;

Lacking variety in shading;

At full length;

With flat sails;

Below the proper pitch;

Against a flat surface;

In a forthright manner; candidly or frankly;

Wholly or completely;