Alkali — a basic (as opposed to acidic) chemical substance or group of substances. Commonly written in katakana.
強いアルカリは皮膚に触れると危険だ。
Strong alkalis are dangerous if they come into contact with the skin.
pHが高い溶液はアルカリ性と呼ばれる。
A solution with a high pH is called alkaline.