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[kol-oid] /ˈkɒl ɔɪd/
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 cm 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.
Medicine/Medical. a colloidal substance in the body, as a stored secretion or a cyst.
Physical Chemistry. colloidal.
Origin of colloid
1840-50; < Greek kóll(a) glue + -oid
Related forms
noncolloid, noun
semicolloid, noun Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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British Dictionary definitions for colloid


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 membrane Compare crystalloid (sense 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
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
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Word Origin and History for colloid

1847, from French colloide (1845), from Greek kolla "glue" + -oeides "form" (see -oid).

Online Etymology Dictionary, © 2010 Douglas Harper
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colloid in Medicine

colloid col·loid (kŏl'oid')

  1. A suspension of finely divided particles in a continuous medium from which the particles do not settle out rapidly and are not readily filtered.

  2. The particulate matter so suspended.

  3. The gelatinous stored secretion of the thyroid gland, consisting mainly of thyroglobulin.

  4. Gelatinous material resulting from colloid degeneration in diseased tissue. Also called colloidin.

Of, relating to, containing, or having the nature of a colloid.
col·loi'dal (kə-loid'l, kŏ-) adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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colloid in Science
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 © 2002. Published by Houghton Mifflin. All rights reserved.
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colloid in Culture
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.

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