[ kol-oid ]
/ ˈkɒl ɔɪd /
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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.Compare aerosol, emulsion, gel, sol4, suspension.
Medicine/Medical. a colloidal substance in the body, as a stored secretion or a cyst.


Physical Chemistry. colloidal.



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Origin of colloid

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


non·col·loid, nounsem·i·col·loid, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

How to use colloid in a sentence

British Dictionary definitions for colloid

/ (ˈkɒlɔɪd) /


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
the solid suspended phase in such a mixture
obsolete a substance that in solution does not penetrate a semipermeable membraneCompare crystalloid (def. 2)
physiol a gelatinous substance of the thyroid follicles that holds the hormonal secretions of the thyroid gland


pathol of or relating to the gluelike translucent material found in certain degenerating tissues
of, denoting, or having the character of a colloid

Word Origin for colloid

C19: from Greek kolla glue + -oid
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

Medical definitions for colloid

[ kŏloid′ ]


A suspension of finely divided particles in a continuous medium from which the particles do not settle out rapidly and are not readily filtered.
The particulate matter so suspended.
The gelatinous stored secretion of the thyroid gland, consisting mainly of thyroglobulin.
Gelatinous material resulting from colloid degeneration in diseased tissue.colloidin


Of, relating to, containing, or having the nature of a colloid.

Other words from colloid

col•loidal (kə-loidl, kŏ-) adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Scientific definitions for colloid

[ kŏloid′ ]

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. Compare solution suspension.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for colloid

[ (kol-oyd) ]

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.

notes for colloid

Fog, paints, and foam rubber are colloids.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.