Adjacent Words

Potassium definitions

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Webster's 1828 Dictionary

POTAS'SIUM, n. A name given to the metallic basis of vegetable alkali. According to Dr. Davy, 100 parts of potash consist of 86.1 parts of the basis, and 13.9 of oxygen.
Potassium has the most powerful affinity for oxygen of all substances known; it takes it from every other compound, and hence is a most important agent in chimical analysis.

WordNet (r) 3.0 (2005)

n
1: a light soft silver-white metallic element of the alkali metal group; oxidizes rapidly in air and reacts violently with water; is abundant in nature in combined forms occurring in sea water and in carnallite and kainite and sylvite [syn: potassium, K, atomic number 19]

Merriam Webster's

noun Usage: often attributive Etymology: New Latin, from potassa potash, from English potash Date: circa 1807 a silver-white soft light low-melting monovalent metallic element of the alkali metal group that occurs abundantly in nature especially combined in minerals — see element table

Dictionary of the Elements

potassium
Symbol: K
Atomic number: 19
Atomic weight: 39.0983
Soft silvery metallic element belonging to group 1 of the periodic table (alkali metals). Occurs naturally in seawater and a many minerals. Highly reactive, chemically, it resembles sodium in its behavior and compounds. Discovered by Sir Humphry Davy in 1807.

Oxford Reference Dictionary

n. Chem. a soft silver-white metallic element occurring naturally in seawater and various minerals, an essential element for living organisms, and forming many useful compounds used industrially. Usage: Symb.: K. Phrases and idioms: potassium chloride a white crystalline solid used as a fertilizer and in photographic processing. potassium cyanide a highly toxic solid that can be hydrolysed to give poisonous hydrogen cyanide gas: also called CYANIDE. potassium iodide a white crystalline solid used as an additive to table salt to prevent iodine deficiency. potassium permanganate a purple crystalline solid that is used in solution as an oxidizing agent and disinfectant. Derivatives: potassic adj. Etymology: POTASH + -IUM

Webster's 1913 Dictionary

Potassium Po*tas"si*um, n. [NL. See Potassa, Potash.] (Chem.) An Alkali element, occurring abundantly but always combined, as in the chloride, sulphate, carbonate, or silicate, in the minerals sylvite, kainite, orthoclase, muscovite, etc. Atomic weight 39.0. Symbol K (Kalium). Note: It is reduced from the carbonate as a soft white metal, lighter than water, which oxidizes with the greatest readiness, and, to be preserved, must be kept under liquid hydrocarbons, as naphtha or kerosene. Its compounds are very important, being used in glass making, soap making, in fertilizers, and in many drugs and chemicals. Potassium permanganate, the salt KMnO4, crystallizing in dark red prisms having a greenish surface color, and dissolving in water with a beautiful purple red color; -- used as an oxidizer and disinfectant. The name chameleon mineral is applied to this salt and also to potassium manganate. Potassium bitartrate. See Cream of tartar, under Cream.

Collin's Cobuild Dictionary

Potassium is a soft silvery-white chemical element, which occurs mainly in compounds. These compounds are used in making such things as glass, soap, and fertilizers.