mid-15c., "primary, original, pertaining to a foundation," modeled on Late Latin fundamentalis "of the foundation," from Latin fundamentum "foundation" (see fundament). In music (1732) it refers to the lowest note of a chord. Fundamentals (n.) "primary principles or rules" of anything is from 1630s.
an example that was fundamental to the argument
computers are fundamental to modern industrial structure
a fundamental incompatibility between them
the fundamental laws of the universe
the book underwent fundamental changes
committed the fundamental error of confusing spending with extravagance
the fundamental revolution in human values that has occurred
fundamentals include a company's growth, revenues, earnings, management, and capital structure
functionalism
functionary
functionless
fund
fundament
fundamental
fundamentalism
fundamentalist
fundamentally
funded
funding