protein

IPA/ˈprəʊtiːn/
KK[prˈotˌin]IPA/ˈprəʊtiːn/

protein — noun

  • proteinsingular
  • proteinsplural

1. A natural substance found in foods such as meat, eggs, fish, cheese, and beans.

1.nounA2
Definition

A natural substance found in foods such as meat, eggs, fish, cheese, and beans. Your body needs it to grow, repair damaged tissues, and stay healthy.

Example

Bao eats eggs and beans every day to get enough protein for his training.

collocation: get enough protein

This brand of yoghurt has twice as much protein as the regular one.

comparative pattern: as much protein as

Common collocations
  • animal protein
  • plant protein
  • lean protein
  • protein intake
  • protein shake
  • protein-rich foods
  • complete protein
Synonyms
  • nutrient

    broader term — any substance that provides nourishment, not just protein

  • amino acids

    related but not synonymous — amino acids are the building blocks that make up protein

Grammar Patterns

protein + in + food type

source of + protein

high in + protein

Usage Note

In everyday use this sense is uncountable ('Protein is important for muscles'). When talking about different kinds of protein-rich foods, it can be countable ('legumes are a good plant protein').

Common Mistakes

I need to eat more proteins.
I need to eat more protein.
In the food sense, 'protein' is usually uncountable. Use the plural 'proteins' only when listing different types of protein-rich foods or sources.

2. Any of many natural chemical compounds found in all living cells. Made from long

2.nounB2
Definition

Any of many natural chemical compounds found in all living cells. Made from long chains of amino acids, each type of protein performs a specific job, such as speeding up chemical reactions, carrying signals, or protecting the body from disease.

Example

Each protein in the human body has a specific shape that allows it to do a particular job.

relative clause describing protein function

Enzymes are a type of protein that speed up chemical reactions inside cells.

pattern: a type of protein that + action

Common collocations
  • structural protein
  • membrane protein
  • protein synthesis
  • protein structure
  • protein molecule
  • recombinant protein
  • protein expression
Synonyms
  • polypeptide

    a more specific term — a chain of amino acids that may form part of or be a protein; used in technical contexts

  • enzyme

    a type of protein that speeds up chemical reactions — narrower than 'protein'

  • macromolecule

    broader category — includes proteins, nucleic acids, and carbohydrates

Grammar Patterns

protein + that + verb/action

type of + protein

protein + in + cell/tissue

Usage Note

This sense is the technical, biological meaning. In academic or scientific writing, 'protein' is countable when referring to individual types ('receptor proteins', 'channel proteins') and uncountable when referring to the substance in general ('Protein makes up 20% of the body').

Common Mistakes

Protein is only found in meat and eggs.
Protein is found in all living cells, not just in food.
The biochemical sense refers to proteins as structural and functional molecules in all organisms, not just as dietary nutrients.

Word family

  • protein-rich
    adjectiveB1
  • proteinaceous
    adjectiveC1
  • proteomics
    nounC2
  • protease
    nounC2
  • proteolytic
    adjectiveC2

Synonym discussion

Sense: noun/1

'Protein' refers specifically to the complex molecules found in food or living cells that are essential for growth and repair. 'Nutrient' is a much broader category — it includes proteins, carbohydrates, fats, vitamins, and minerals. For example, saying 'milk contains many nutrients' covers more than just protein. 'Amino acids' are the smaller building blocks that link together to form proteins; you eat protein, and your body breaks it down into amino acids. 'Proteomics' is the large-scale scientific study of proteins — a field of research, not a substance. For everyday nutrition talk, use 'protein'; for general food value, use 'nutrient'; for the chemical components, use 'amino acids'.

protein ↗nutrient ↗amino acidproteomics

Common collocations

Nouns

  • protein source
  • protein intake
  • protein content
  • protein level
  • protein powder
  • protein shake
  • protein structure
  • protein synthesis

Adverbs

  • highly [protein-rich]
  • biologically [active protein]
  • purely [plant protein]

Phrases

  • high in protein
  • low in protein
  • packed with protein
  • good source of protein
  • protein-rich diet

Prepositions

  • protein in [food/cells]
  • source of protein
  • rich in protein
  • made from protein

Etymology

GreekFrenchEnglish

The word 'protein' was coined in 1838 by the Swedish chemist Jöns Jacob Berzelius. He based it on the French 'protéine', which came from the Greek 'proteios' (πρώτειος), meaning 'primary' or 'of first rank'. Berzelius chose the name because he believed these substances were fundamental — the first and most important compounds in living organisms. The word entered English soon after, first as a scientific term and later in everyday use for dietary nutrition.