Maximum
mid 17th century (as a noun): from modern Latin, neuter (used as a noun) of the Latin adjective maximus, superlative of magnus ‘great’. The adjectival use dates from the early 19th century.
wiktionary
Via French from Latin maximum.
etymonline
maximum (n.)
"the greatest amount, quantity, or degree," 1740, from French maximum and directly from Latin maximum (plural maxima), neuter of maximus "greatest," which is superlative of magnus "great, large, big" (of size), "abundant" (of quantity), "great, considerable" (of value), "strong, powerful" (of force); of persons, "elder, aged," also, figuratively, "great, mighty, grand, important," from PIE *mag-samo-, superlative form of root *meg- "great."
maximum (adj.)
"greatest, at the maximum," 1834, from maximum (n.).
