emulsion

emulsion — noun

1. A stable mixture formed when tiny droplets of one liquid are spread evenly throu

1.nounB2
Definition

A stable mixture formed when tiny droplets of one liquid are spread evenly through another liquid that they would not normally mix with — for example, oil dispersed in vinegar to make vinaigrette, or fat suspended in milk.

Example

Inês mixed oil and vinegar to create a temporary emulsion for her salad dressing.

create a temporary emulsion for [food/liquid]

Milk is a natural emulsion of tiny fat droplets spread throughout water.

Common collocations
  • form an emulsion
  • create an emulsion
  • natural emulsion
  • stable emulsion
  • temporary emulsion
Synonyms
  • colloid

    Broader technical term for any mixture where one substance is dispersed in another, not limited to liquids.

  • suspension

    Describes solid particles floating in a liquid rather than liquid droplets in another liquid.

Antonyms
  • solution

    A homogeneous mixture where one substance dissolves completely in another, unlike an emulsion where the liquids remain separate.

Usage Note

Frequently uncountable when referring to the general concept ("Emulsion forms when you shake oil and water together"), but countable when talking about a specific type ("This is a stable emulsion"). Common in chemistry, cooking, and cosmetics contexts.

Common Mistakes

Oil and water form a solution when shaken.
Oil and water form an emulsion when shaken.
In a solution, one substance dissolves into another; in an emulsion, the liquids remain separate as tiny droplets.

2. A wall paint that has water as its main liquid, dries to a flat finish without s

2.nounB1
Definition

A wall paint that has water as its main liquid, dries to a flat finish without shine, and is commonly used on indoor walls and ceilings.

Example

Eli chose white emulsion for the walls because it dries fast and has no smell.

choose emulsion for [surface]

Salma bought a five-litre tub of matt emulsion to repaint the hallway this weekend.

matt emulsion

Common collocations
  • apply emulsion
  • coat of emulsion
  • white emulsion
  • matt emulsion
  • emulsion paint
  • emulsion finish
Synonyms
  • latex paint

    The American English term for the same product. British speakers rarely use this term.

  • matt paint

    A broader term for any paint that dries without shine, not limited to water-based paints.

Usage Note

In everyday British English, 'emulsion' or 'emulsion paint' is the standard word for water-based wall paint. In American English, this product is usually called 'latex paint'.

Common Mistakes

I bought emulsion for the wooden fence.
I bought outdoor wood paint for the wooden fence.
Emulsion is designed for interior walls and ceilings, not for outdoor surfaces or bare wood.

3. A light-sensitive layer of chemical compounds spread onto photographic film or p

3.nounC1
Definition

A light-sensitive layer of chemical compounds spread onto photographic film or paper, which captures an image when it is exposed to light and then processed.

Example

Traditional film is coated with a light-sensitive emulsion of silver compounds suspended in gelatin.

light-sensitive emulsion of silver compounds

Kemi developed the black-and-white film by immersing the emulsion-coated paper in chemical baths.

emulsion-coated paper

Common collocations
  • photographic emulsion
  • light-sensitive emulsion
  • coat with emulsion
  • emulsion layer
Synonyms
  • film coating

    A non-technical description of the same layer, though less precise.

Usage Note

This sense is now mostly encountered in discussions of traditional film photography. Digital cameras do not use emulsion. The word is uncountable when referring to the substance generally ("The emulsion reacted to the light") but countable when referring to different types ("Modern emulsions are more sensitive than early ones").

Word family

  • emulsify
    verbC1
  • emulsifier
    nounC1

Synonym discussion

Sense: noun/1

These four terms describe different ways substances combine. A 'solution' is the most complete mixing — the substances dissolve at a molecular level, like salt in water, and you cannot see the individual particles. An 'emulsion' is a specific type of 'colloid' where both substances are liquids and one forms tiny droplets within the other (mayonnaise is a classic example). A 'suspension' involves solid particles floating in a liquid; unlike an emulsion, these particles eventually settle if left undisturbed. 'Mixture' is the broadest term — it covers any combination of substances, from a salad (a coarse mixture) to a solution (a molecular-level mixture). For everyday cooking, 'emulsion' is the precise word when describing vinaigrette, mayonnaise, or hollandaise: the oil droplets are visibly separate from the vinegar or egg yolks.

colloidsuspension ↗solution ↗mixture ↗

Common collocations

Nouns

  • emulsion paint
  • emulsion finish
  • emulsion layer
  • emulsion coating

Phrases

  • form an emulsion
  • create an emulsion

Prepositions

  • in emulsion
  • of emulsion

Etymology

LatinFrenchEnglish

The word 'emulsion' comes from the Latin verb 'emulgēre', meaning 'to milk out' — formed from 'ex-' (out of) and 'mulgēre' (to milk). The connection is visual: when milk is drawn from an animal, it naturally forms a milky-white mixture of fat droplets suspended in water, which is one of the most familiar emulsions. The term entered English in the early 1600s as a medical term for milky liquid mixtures, and by the 1800s it was being used in chemistry and photography for any liquid-in-liquid dispersion.