n.; pl. Alkalis or Alkalies [ F. alcali, ultimately fr. Ar. alqalī ashes of the plant saltwort, fr. qalay to roast in a pan, fry. ] 1. Soda ash; caustic soda, caustic potash, etc. [ 1913 Webster ]

2. (Chem.) One of a class of caustic bases, such as soda, potash, ammonia, and lithia, whose distinguishing peculiarities are solubility in alcohol and water, uniting with oils and fats to form soap, neutralizing and forming salts with acids, turning to brown several vegetable yellows, and changing reddened litmus to blue. [ 1913 Webster ]

3. Soluble mineral matter, other than common salt, contained in soils of natural waters. [ Western U. S. ] [ Webster 1913 Suppl. ]

Fixed alkalies, potash and soda. --
Vegetable alkalies. Same as Alkaloids. --
Volatile alkali, ammonia, so called in distinction from the fixed alkalies. [ 1913 Webster ]

adj. 1. having the properties of an alkali. Opposite of acidic. when used of aqueous solutions, it signifies that the solution has a pH greater than 7.
Syn. -- alkaline (vs. acidic), basic [ WordNet 1.5 ]

a. [ Cf. F. alcalifiable. ] Capable of being alkalified, or converted into an alkali. [ 1913 Webster ]

. A sterile plain, containing an excess of alkali, at the bottom of an undrained basin in an arid region; a playa. [ Webster 1913 Suppl. ]

v. t. [ imp. & p. p. Alkalified p. pr. & vb. n. Alkalifying. ] [ Alkali + -fly: cf. F. alcalifier. ] To convert into an alkali; to give alkaline properties to. [ 1913 Webster ]

v. i. To become changed into an alkali. [ 1913 Webster ]

. Any one of the univalent metals of group I of the periodic table of the elements, including lithium, sodium, potassium, rubidium, cesium, and francium. The hydroxides of these metals are soluble in water and form strongly basic solutions. [ PJC. ]

n. [ Alkali + -meter. cf. F. alcalimètre. ] An instrument to ascertain the strength of alkalies, or the quantity of alkali in a mixture. [ 1913 Webster ]

{ } a. Of or pertaining to alkalimetry. [ 1913 Webster ]

n. [ Cf. F. alcalimètrie. ] (Chem.) The art or process of ascertaining the strength of alkalies, or the quantity present in alkaline mixtures. [ 1913 Webster ]