Of, relating to, or forming a base; fundamental: "Basic changes in public opinion often occur because of shifts in concerns and priorities\u201d ( Atlantic). Of, being, or serving as a starting point or basis: a basic course in Russian; a set of basic woodworking tools. Chemistry Of or relating to a base. Chemistry Containing a base, especially in excess of acid. Chemistry Alkaline. Geology Containing little silica, as igneous rocks. An essential, fundamental element or entity: the basics of math. Basic training.