/ˈælkəlaɪ / (say 'alkuhluy)

noun (plural alkalis or alkalies)
1. Chemistry
a. any of various bases, the hydroxides of the alkali metals and of ammonium, which neutralise acids to form salts and turn red litmus paper blue.
b. any of various other more or less active bases, as calcium hydroxide.
c. Obsolescent any of various other compounds, as the carbonates of sodium and potassium.
2. Agriculture a soluble mineral salt, or a mixture of soluble salts, occurring in soils, etc., usually to the damage of crops.
{Middle English alkaly, from Middle French alcali, from Arabic al qily, later al qalī the saltwort ashes}

Australian English dictionary. 2014.