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colloid

American  
[kol-oid] / ˈkɒl ɔɪd /

noun

  1. Physical Chemistry. a substance made up of a system of particles with linear dimensions in the range of about 10 −7 to 5 × 10 −5 centimeters dispersed in a continuous gaseous, liquid, or solid medium whose properties depend on the large specific surface area. The particles can be large molecules like proteins, or solid, liquid, or gaseous aggregates and they remain dispersed indefinitely.

  2. Medicine/Medical. a colloidal substance in the body, as a stored secretion or a cyst.


adjective

  1. Physical Chemistry. colloidal.

colloid British  
/ ˈkɒlɔɪd /

noun

  1. Also called: colloidal solution, colloidal suspension. a mixture having particles of one component, with diameters between 10 –7 and 10 –9 metres, suspended in a continuous phase of another component. The mixture has properties between those of a solution and a fine suspension

  2. the solid suspended phase in such a mixture

  3. obsolete a substance that in solution does not penetrate a semipermeable membrane Compare crystalloid

  4. physiol a gelatinous substance of the thyroid follicles that holds the hormonal secretions of the thyroid gland

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

adjective

  1. pathol of or relating to the gluelike translucent material found in certain degenerating tissues

  2. of, denoting, or having the character of a colloid

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
colloid Scientific  
/ kŏl′oid′ /
  1. A mixture in which very small particles of one substance are distributed evenly throughout another substance. The particles are generally larger than those in a solution, and smaller than those in a suspension. Paints, milk, and fog are colloids.

  2. Compare solution suspension


colloid Cultural  
  1. A substance made up of particles that are larger than most molecules; these particles do not actually dissolve in substances but stay suspended in them.


Discover More

Fog, paints, and foam rubber are colloids.

Other Word Forms


Etymology

Origin of colloid

First recorded in 1840–50; from Greek kóll(a) “glue” + -oid


Vocabulary lists containing colloid

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

"Our far-reaching theory encompasses all systems evidencing such transverse interactions. Conceivable applications range from colloid research to biology," declares co-author Dr. Michael te Vrugt, Assistant Professor at the University of Mainz.

From Science Daily ● Oct. 21, 2025

In November, she underwent surgery after a colloid cyst was found earlier that month during a health check-up as part of her menopause advocacy work.

From BBC ● Sep. 13, 2025

The former Big Brother host underwent surgery in November after a colloid cyst was found earlier that month during a health check-up as part of her menopause advocacy work.

From BBC ● Apr. 12, 2025

The particles in a colloid are larger than most simple molecules;

From Textbooks ● Feb. 14, 2019

When a solute is introduced into a colloidal solution, the greater the concentration of the colloid the slower will be the diffusion.

From The Mechanism of Life by Stéphane Leduc

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