Fundamental means forming the base that everything else rests on. A fundamental principle, fundamentally different, fundamental rights.
Fundamentally different means different at the root, not merely very different, and it is worth keeping that strength. In music the fundamental is the lowest frequency of a note, and the harmonics above it decide what instrument you hear. The Latin means a foundation.
1adjectivefundamentalForming the base that everything else rests on.
“Freedom of speech is a fundamental right in a democracy.”
fundamental is a quality of basis.
Latin fundamentalis comes from fundamentum, a foundation, from fundare, to lay a base, from fundus, the bottom.
Latin
fundāmentālis
Middle English
foundamental,fundamental
English, today
fundamental
Built from
From Middle English foundamental,fundamental, from Latin fundāmentālis, from Latin fundāmentum (“foundation”), from fundō (“to lay the foundation (of something), to found”), from fundus (“bottom”), from Proto-Indo-European bʰudʰmḗn. by surface analysis, fundament + -al.
Etymology from Wiktionary, CC BY-SA