fundamental
1. [ adjective ] serving as an essential component
Synonyms: central key cardinal primal
Examples:

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

Related terms: important
2. [ adjective ] being or involving basic facts or principles
Synonyms: rudimentary underlying
Examples:

"the fundamental laws of the universe" "a fundamental incompatibility between them" "these rudimentary truths" "underlying principles"

Related terms: basic
3. [ adjective ] far-reaching and thoroughgoing in effect especially on the nature of something
Synonyms: profound
Examples:

"the fundamental revolution in human values that has occurred" "the book underwent fundamental changes" "committed a fundamental error" "profound social changes"

Related terms: significant
4. [ noun ] (psychology) the lowest tone of a harmonic series
Synonyms: first_harmonic fundamental_frequency
Related terms: harmonic
Similar spelling:   fundamentals
  fundamentally
  fundament
  fundamentalist
  fundamentalism