- the lowest tone of a harmonic series

- serving as an essential component
"a cardinal rule"
"the central cause of the problem"
"an example that was fundamental to the argument"
"computers are fundamental to modern industrial structure"

- being or involving basic facts or principles
"the fundamental laws of the universe"
"a fundamental incompatibility between them"
"these rudimentary truths"
"underlying principles"

- far-reaching and thoroughgoing in effect especially on the nature of something
"the fundamental revolution in human values that has occurred"
"the book underwent fundamental changes"
"committed the fundamental error of confusing spending with extravaga

1. Pertaining to the foundation or basis; serving for the foundation. Hence: Essential, as an element, principle, or law; important; original; elementary; as, a fundamental truth; a fundamental axiom.

"The fundamental reasons of this war." -- Shak.

"Some fundamental antithesis in nature." -- Whewell.

Fundamental bass
(Mus.), the root note of a chord; a bass formed of the roots or fundamental tones of the chords.

Fundamental chord
(Mus.), a chord, the lowest tone of which is its root.

Fundamental colors
red, green, and violet-blue. See Primary colors, under Color.

1. 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.