the word "substantially" is built upon the latin foundation "substantia," meaning "essence, material, or that which stands under." the core root "sta-" (to stand, make firm) is of proto-indo-european origin, giving rise to concepts of stability and reality. the prefix "sub-" (under) combined with "stant-" (standing) literally evokes the idea of "that which stands under" as a supporting foundation or true essence. over time, the adjective "substantial" evolved to describe something of considerable size, importance, or solidity, and the adverbial form "substantially" naturally came to signify the manner of being so—to a great extent or in a firm, material way.

Structure: sub (under) + stant (stand) + ial (adjective suffix) + ly (adverb suffix) - sub: a latin prefix meaning "under, below, from below." - stant: from the latin root "stare" (to stand), present participle stem "stant-". - ial: a latin-derived suffix forming adjectives meaning "of or relating to." - ly: an old english suffix forming adverbs from adjectives.