depth

depth — noun

1. How far down something goes, measured from its surface or top edge to its bottom

1.nounA2
Definition

How far down something goes, measured from its surface or top edge to its bottom.

Example

The swimming pool has a depth of two metres at the deep end.

collocation: has a depth of [number]

Divers measured the depth of the lake before the team started building the bridge.

Common collocations
  • depth of [number] [unit]
  • at a depth of
  • full depth
  • shallow depth
Synonyms
  • deepness

    less common; used for physical depth in everyday speech

Antonyms

Grammar Patterns

depth + of + number + unit

Usage Note

Uncountable when referring to the abstract quality; countable when stating a specific measurement (e.g. 'a depth of 3 metres').

Common Mistakes

The depth of the river is 5 metres deep.
The depth of the river is 5 metres.
'depth' already includes the idea of 'deepness'; adding 'deep' is redundant.

2. The part of the ocean or a large body of water that is far below the surface, wh

2.nounB1
Definition

The part of the ocean or a large body of water that is far below the surface, where the water is deep, dark, and far down.

Example

The fish live in the depths of the Pacific Ocean.

the depths of [place]

Creatures in the depths of the sea have adapted to complete darkness.

Common collocations
  • the depths of the sea/ocean
  • descend into the depths
  • dark depths
  • ocean depths
Synonyms
  • abyss

    more dramatic and literary; suggests an extremely deep, seemingly bottomless space

  • deep

    poetic or literary alternative; used as a noun mainly in fixed expressions ('the deep')

Antonyms
  • surface

    the top layer of water, as opposed to the depths below

Grammar Patterns

the depths of [place]

Usage Note

Almost always used in the plural form 'depths', especially in literary or descriptive writing.

3. The quality of being serious, complex, and involving careful thought or detailed

3.nounB2
Definition

The quality of being serious, complex, and involving careful thought or detailed understanding, rather than being simple or superficial.

Example

The professor's lecture had great depth and made everyone think more carefully.

This novel has a surprising depth for a story aimed at younger readers.

Common collocations
  • great depth
  • lack depth
  • depth of understanding/knowledge/analysis
  • depth of character
Synonyms
  • profundity

    more formal and literary; emphasises intellectual or spiritual depth

  • substance

    focuses on having meaningful content rather than being empty or trivial

Antonyms

Grammar Patterns

depth + of + abstract noun

Usage Note

Subject is often a piece of work (writing, film, speech) or a person's knowledge. Contrasts with 'superficiality' or 'shallowness'.

Common Mistakes

This book has a lot of depth.
This book has great depth.
'a lot of' is informal and less natural; use 'great depth' or 'real depth' for this abstract sense.

4. The state of being thorough, careful, and complete, covering every important det

4.nounB2
Definition

The state of being thorough, careful, and complete, covering every important detail of a subject or issue.

Example

The committee's report examines each stage of the process in great depth.

in great depth

The journalist investigated the case in depth before writing the article.

in depth

Common collocations
  • in depth
  • in great depth
  • examine/study/cover/discuss in depth
Synonyms
  • thoroughness

    direct synonym; focuses on completeness and attention to detail

  • detail

    useful in the phrase 'in detail' as an alternative to 'in depth'

Antonyms
  • superficially

    done in a shallow or incomplete way, without attention to detail

Grammar Patterns

in depth

in great depth

Usage Note

Almost always appears in the fixed adverbial phrase 'in depth' or 'in great depth'. This is different from 'with depth' (Sense 3 — intellectual substance). 'In depth' describes HOW something is done, not the quality of the thing itself.

Common Mistakes

We discussed the problem depth.
We discussed the problem in depth.
The preposition 'in' is required for this sense.

5. The measurement from the front of something to its back, used for furniture, roo

5.nounA2
Definition

The measurement from the front of something to its back, used for furniture, rooms, shelves, and other objects with a front and back side.

Example

The kitchen cupboard is 60 centimetres in depth and 80 wide.

collocation: [number] in depth

Check the depth of the shelf before you buy the storage boxes.

Common collocations
  • in depth
  • [number] [unit] in depth
  • shelf/desk/cupboard/drawer depth

Grammar Patterns

depth + of + number + unit

Usage Note

Distinguish from 'width' (side-to-side) and 'height' (top-to-bottom). In furniture and architecture, depth is the front-to-back dimension, while width is side-to-side.

Common Mistakes

❌ 'The desk is 120 centimetres wide and 60 centimetres deep.' — This is correct when using the adjective 'deep', not a mistake. Just be aware that 'depth' is the noun form.

6. The fact that a feeling, emotion, experience, or situation is extremely strong,

6.nounB2
Definition

The fact that a feeling, emotion, experience, or situation is extremely strong, powerful, and deeply felt rather than mild or surface-level.

Example

The depth of Yasmin's grief surprised everyone who knew her.

the depth of [emotion]

Felix did not know the depth of his father's anger until his father shouted.

Common collocations
  • the depth of [emotion/feeling]
  • depth of despair/grief/anger/love
  • depth of the crisis/recession/problem
Synonyms
  • intensity

    focuses on the strength of the feeling; more factual and less literary than 'depth'

  • severity

    used specifically for negative situations such as crises or problems

Antonyms
  • mildness

    a low degree of emotional strength

Grammar Patterns

the depth of [emotion/experience]

Usage Note

Frequently used with negative emotions (grief, despair, anger) or serious problems (crisis, recession). When used with positive emotions (love, joy), it often implies a moment of realisation.

7. a rich and satisfying quality in food or drink that makes it taste full and well

7.nounB2
Definition

a rich and satisfying quality in food or drink that makes it taste full and well-developed, often achieved through slow cooking, quality ingredients, or ageing.

Example

The mushroom soup Gabriel made had a surprising depth of flavour.

collocation: depth of flavour

Marco chose the red wine for its depth and long, smooth finish.

Common collocations
  • depth of flavour
  • depth of taste
  • give depth
  • lack depth
  • add depth
Synonyms
  • richness

    focuses on the full, intense quality; 'depth' adds the idea of layers of flavour

  • intensity

    more general; 'depth' implies a pleasant, developed intensity rather than just strength

  • complexity

    highlights the variety of flavour notes; 'depth' suggests a single rich quality

Antonyms
  • shallowness

    of flavour — lacking depth or fullness

  • flatness

    describes a dull, one-dimensional taste without richness

Grammar Patterns

depth of [flavour/taste]

Usage Note

Commonly appears in the phrases 'depth of flavour' and 'depth of taste'. Typically describes complex cooked dishes, aged cheeses, and fermented or slow-brewed drinks such as wine, coffee, or broth — not simple or raw ingredients.

Common Mistakes

This soup has depth flavour.
This soup has depth of flavour.
'depth' requires 'of' before the quality described.

8. how dark and rich a colour looks, especially when it is strong rather than pale

8.nounB2
Definition

how dark and rich a colour looks, especially when it is strong rather than pale or light.

Example

The artist painted layer after layer to give the sky more depth of blue.

pattern: depth of [colour name]

Heloísa stood watching the depth of red spread across the evening sky.

Common collocations
  • depth of colour
  • depth of blue/red/purple
  • give depth
  • rich in depth
  • depth and richness
Synonyms
  • intensity

    broader than 'depth'; can describe any strength of colour, including bright ones

  • richness

    similar to 'depth' but emphasises the luxurious or full quality rather than the darkness

  • saturation

    a technical term used in colour theory; 'depth' is more natural in everyday language

Antonyms
  • paleness

    lightness of colour — the opposite of richness and darkness

  • flatness

    describes colour that lacks variation or depth

Grammar Patterns

depth of [colour]

Usage Note

Typically used with dark or intense colours such as blue, red, purple, and green — not with pastels or pale shades. Often found in descriptions of painting, photography, fabric, and natural scenery.

Common Mistakes

I like the depth colour of this paint.
I like the depth of colour of this paint.
the noun 'depth' needs an 'of' phrase.

9. how low a sound or voice is on the musical scale, creating a full and resonant t

9.nounB2
Definition

how low a sound or voice is on the musical scale, creating a full and resonant tone.

Example

Christopher's voice had a natural depth that suited radio announcing perfectly.

collocation: depth of voice

Eri loved how the cello's low notes filled the hall with warmth and depth.

Common collocations
  • depth of sound
  • depth of voice
  • gain depth
  • add depth
  • natural depth
Synonyms
  • resonance

    emphasises how the sound vibrates and carries; more technical than 'depth'

  • bass

    describes the low-frequency range; 'depth' is more about the quality of the low sound

  • fullness

    suggests a rich, complete sound; 'depth' adds the idea of a low register

Antonyms
  • thinness

    describes a weak, high-pitched sound with no body

  • shrillness

    describes an unpleasant high-pitched sound

Grammar Patterns

depth of [sound/voice/tone]

Usage Note

Often describes a voice (especially a man's) or a musical instrument such as a cello, double bass, organ, or bass guitar. The depth of a sound is something you can feel physically through vibration as well as hear.

Common Mistakes

His voice has depth and clear.
His voice has depth and clarity.
use the noun form 'clarity' after 'depth and'.
Idioms

be out of your depth

idiom

To be in a situation that is too difficult for you to handle.

Maya felt out of her depth in the advanced calculus class.

If you can't swim, don't go out of your depth in the lake.

in depth

idiom

In a very detailed and thorough manner.

The professor explained the theory in depth during the lecture.

Have you studied the contract in depth before signing it?

plumb the depths of something

idiom

To experience the worst possible level of something unpleasant.

The movie plumbs the depths of human cruelty and despair.

After losing his job, he plumbed the depths of depression.

strength in depth

idiom

Having many capable people or resources available to ensure success.

The soccer team's strength in depth helped them win the championship.

Our company has strength in depth with experts in every field.

Word family

Synonym discussion

Sense: noun/3

depth（深度）是日常英語中最通用的詞，涵蓋具體物理深度與抽象深刻性。profundity（深奧、深邃）偏向正式與文學用法，專指思想、智慧或哲學上的高度深刻，例如 the profundity of Einstein's theories。deepness 語義與 depth 幾乎相同，但現代英語中使用頻率遠低於 depth，主要出現在具體可測量的語境（the deepness of the cut），或在非正式口語中替代 depth。概括而言：談具體深度或一般性的「深入」用 depth；強調思想哲理上的深奧用 profundity；而 deepness 雖然正確，但多數情況下以 depth 取代更自然。例如：The depth of her research impressed the committee.（通用）→ The profundity of her philosophical insights was remarkable.（正式、抽象）→ The deepness of the wound worried the nurse.（具體，略嫌冗贅，用 depth 更佳）

depth ↗profunditydeepness

Common collocations

Nouns

  • depth of field — 景深（攝影）
  • depth of flavour — 濃郁風味
  • depth of colour — 色彩濃厚度
  • depth of feeling — 情感深度
  • depth of knowledge — 知識深度
  • depth of understanding — 理解深度
  • depth of character — 性格深度
  • depth of the ocean — 海洋深度
  • depth of the crisis — 危機嚴重程度

Adverbs

  • great depth
  • considerable depth
  • remarkable depth
  • surprising depth
  • sufficient depth

Phrases

  • in depth — 詳細地、徹底地（adv. phrase）
  • the depths of — …的深處（常用複數）
  • plumb the depths — 達到最低點；徹底經歷
  • out of one's depth — 力不從心；無法理解
  • strength in depth — （隊伍、組織）人才濟濟
  • hide the depths — 隱藏深層含義
  • full depth — 全深度；完全深入

Prepositions

  • in depth — 深入、徹底
  • at a depth of — 在…深度
  • to a depth of — 達到…深度
  • from the depths — 從深處
  • beyond the depth — 超過…深度
  • out of one's depth — 超出某人能力範圍

Etymology

原始印歐語原始日耳曼語古英語中古英語現代英語

源自中世紀古英語 dīepth 或 dȳpþ，由形容詞 dēop（「深的」）加上名詞後綴 -th 構成。這個後綴也用於 length（長度）、width（寬度）、strength（力量）等名詞。古英語的 dēop 可追溯至原始日耳曼語 deupaz，與古高地德語 tiof、古斯堪地納維亞語 djúpr 同源，最終來自原始印歐語根 *dʰewb-（「深、空洞」）。