1 : being or involving basic facts or principles; "the fundamental laws of the universe"; "a fundamental incompatibility between them"; "these rudimentary truths"; "underlying principles"
2 : forming or having the nature of a turning point or crisis; "a critical point in the campaign"; "the critical test"
3 : 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"
