|1.||[ adjective ] serving as an essential component|
|Synonyms:||central key cardinal primal|
"a cardinal rule" "the central cause of the problem" "an example that was fundamental to the argument" "computers are fundamental to modern industrial structure"
|2.||[ adjective ] being or involving basic facts or principles|
"the fundamental laws of the universe" "a fundamental incompatibility between them" "these rudimentary truths" "underlying principles"
|3.||[ adjective ] 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 a fundamental error" "profound social changes"
|4.||[ noun ] (psychology) the lowest tone of a harmonic series|