fundamental vs part of

fundamental

noun

  • The lowest frequency of a periodic waveform. 

  • A main or major principle, rule, law, etc. which serves as the foundation or basis of a system; an essential part 

  • The lowest partial of a complex tone. 

adj

  • Related to a foundation. base, or basis; serving as a foundation. 

  • essential; extremely important 

part of

How often have the words fundamental and part of occurred in a corpus of books? (source: Google Ngram Viewer )