colloid

[ kol-oid ]

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. Compare aerosol, emulsion, gel, sol ⁴, suspension.
2. Medicine/Medical. a colloidal substance in the body, as a stored secretion or a cyst.

adjective

1. Physical Chemistry. colloidal.

colloid

/ ˈkɒlɔɪd /

noun

1. Also calledcolloidal solutioncolloidal suspension a mixture having particles of one component, with diameters between 10 ^–7and 10 ^–9metres, 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. See crystalloid
   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

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

colloid

/ 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

colloid

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.

Notes

Fog, paints, and foam rubber are colloids.

Other Words From

• non·colloid noun
• semi·colloid noun

Word History and Origins

Origin of colloid¹

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

Word History and Origins

Origin of colloid¹

C19: from Greek kolla glue + -oid

Example Sentences

The charge on a colloid seems to be liable to variation with the nature of the liquid in which it is suspended.

From Project Gutenberg

In fact, no exact knowledge of the source of electrification of any colloid has yet been obtained.

From Project Gutenberg

We may even have one and the same substance—either organic or inorganic—in both conditions, as crystal or as colloid.

From Project Gutenberg

A colloid globule suspended in a salt solution in which it is not dissolved may grow by intussusception.

From Project Gutenberg

There remains the question of the precipitation of the tanning colloid at the interface.

From Project Gutenberg