Webster's Revised Unabridged Dictionary · 1913

Fundamental

Fundamental , adjective

[Compare French fondamental.]

Pertaining to the foundation or basis; serving for the foundation.
Essential, as an element, principle, or law; important; original; elementary; as, a fundamental truth; a fundamental axiom.
The fundamental reasons of this war. — Shakespeare
Some fundamental antithesis in nature. — Whewell
Collocations (3)
Fundamental bass (Music) , the root note of a chord; a bass formed of the roots or fundamental tones of the chords.
Fundamental chord (Music) , a chord, the lowest tone of which is its root.
Fundamental colors , red, green, and violet-blue. See Primary colors, under Color.

Fundamental , noun

A leading or primary principle, rule, law, or article, which serves as the groundwork of a system; essential part, as, the fundamentals of the Christian faith.