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The Collaborative International Dictionary

Colloid \Col"loid\, a. [Gr. ko`lla glue + -oid. Cf. Collodion.] Resembling glue or jelly; characterized by a jellylike appearance; gelatinous; as, colloid tumors.


Colloid \Col"loid\, n.

  1. (Physiol. Chem.) A substance (as albumin, gum, gelatin, etc.) which is of a gelatinous rather than a crystalline nature, and which diffuses itself through animal membranes or vegetable parchment more slowly than crystalloids do; -- opposed to crystalloid.

  2. (Med.) A gelatinous substance found in colloid degeneration and colloid cancer.

    Styptic colloid (Med.), a preparation of astringent and antiseptic substances with some colloid material, as collodion, for ready use.

Douglas Harper's Etymology Dictionary

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


a. glue-like; gelatinous. n. 1 (context chemistry English) A stable system of two phases, one of which is dispersed in the other in the form of very small droplets or particles. 2 (context meteorology English) An intimate mixture of two substances one of which, called the dispersed phase (or '''colloid'''), is uniformly distributed in a finely divided state throughout the second substance, called the dispersion medium (or dispersing medium). The dispersion medium may be a gas, a liquid, or a solid, and the dispersed phase may also be any of these, with the exception that one does not speak of a colloidal system of one gas in another. A system of liquid or solid particles colloidally dispersed in a gas is called an aerosol. A system of solid substances or water-insoluble liquids colloidally dispersed in liquid water is called a hydrosol. 3 (context geology English) A particle less than 1 micron in diameter, following the Wentworth scale


n. a mixture with properties between those of a solution and fine suspension


A colloid, in chemistry, is a mixture in which one substance of microscopically dispersed insoluble particles is suspended throughout another substance. Sometimes the dispersed substance alone is called the colloid; the term colloidal suspension refers unambiguously to the overall mixture (although a narrower sense of the word suspension is distinguished from colloids by larger particle size). Unlike a solution, whose solute and solvent constitute only one phase, a colloid has a dispersed phase (the suspended particles) and a continuous phase (the medium of suspension). To qualify as a colloid, the mixture must be one that does not settle or would take a very long time to settle appreciably.

The dispersed-phase particles have a diameter between approximately 1 and 1000 nanometers. Such particles are normally easily visible in an optical microscope, although at the smaller size range (r<250 nm), an ultramicroscope or an electron microscope may be required. Homogeneous mixtures with a dispersed phase in this size range may be called colloidal aerosols, colloidal emulsions, colloidal foams, colloidal dispersions, or hydrosols. The dispersed-phase particles or droplets are affected largely by the surface chemistry present in the colloid.

Some colloids are translucent because of the Tyndall effect, which is the scattering of light by particles in the colloid. Other colloids may be opaque or have a slight color.

Colloidal suspensions are the subject of interface and colloid science. This field of study was introduced in 1861 by Scottish scientist Thomas Graham.

Usage examples of "colloid".

He found that smokeless power is produced by colloiding nitrocellulose with special solvents followed by a drying process and that the nitroglycerine bonded with the nitrocellulose and would not separate in storage.

An example of a colloid is found in the albumin of an egg, which is unable to penetrate the membrane which surrounds it.

Paul a whit behind when he succeeded in producing laboratory colloids exhibiting amoeba-like activities, and when he cast new light upon the processes of fertilization through his startling experiments with simple sodium chlorides and magnesium solutions on low forms of marine life.

But they do exchange quantities of complex colloids monthly, presumably sharing data.

Her neck muscles ached, the colloid was thudding in the veins in her temples, she felt like throwing up.

The slow bending of the valve from the weight of particles of glass and even of boxwood, though largely supported by the water, is, I suppose, analogous to the slow bending of colloid substances.

He bent over and saw the red, bleeding skin on the chest, pulpy green below that, and the pale colloid ribs that supported.

It showed the same distinctive permanent colloid pattern as the sample he had ready for comparison.

I'm not contending that colloids are not the fabric of living tissuethey are.

Of course mine was greased, which proved that the Vestal Virgins had a practical understanding of colloid chemistry.

My data processing system has mimicked a colloid mind to short-circuit my decision tree.

No matter how/many follicles form and how much colloid is produced, the thyroid hormone cannot be manufactured without iodine.

His body had been around for a while, and his personality and odd subaware stuff were still clinging to his artificial neurodes and dendrites and synaptic colloids, but he had no substantial memory of his past.

New chapters opened up in the physics of colloids, in the physics of strong interactions, in neutrino astronomy, in nucleonics, biology, and, above all, the new knowledge of the Universe -- this represents but the first interest that has accrued to us from the informational principal, which, according to the experts, promises huge profits to come.