fundamental: Meaning and Definition of

fun•da•men•tal

1. serving as, or being an essential part of, a foundation or basis; basic; underlying: fundamental principles; the fundamental structure.
2. of, pertaining to, or affecting the foundation or basis: a fundamental revision.
3. being an original or primary source: a fundamental idea.
4. (of a chord) having its root as its lowest note.

1. a basic principle, rule, law, or the like, that serves as the groundwork of a system; essential part: to master the fundamentals of a trade.
2. Also called
1. the root of a chord.
2. the generator of a series of harmonics.
3. the component of lowest frequency in a composite wave.