Old English mara "greater, relatively greater, more, stronger, mightier," used as a comparative of micel "great" (see mickle), from Proto-Germanic *maiz (source also of Old Saxon mera, Old Norse meiri, Old Frisian mara, Middle Dutch mere, Old High German meriro, German mehr, Gothic maiza), from PIE *meis- (source also of Avestan mazja "greater," Old Irish mor "great," Welsh mawr "great," Greek -moros "great," Oscan mais "more"), perhaps from a root *me- "big."
Sometimes used as an adverb in Old English ("in addition"), but Old English generally used related ma "more" as adverb and noun. This became Middle English mo, but more in this sense began to predominate in later Middle English.
"Take some more tea," the March Hare said to Alice, very earnestly.
"I've had nothing yet," Alice replied in an offended tone, "so I can't take more."
"You mean you can't take less," said the Hatter: "it's very easy to take more than nothing."
As a noun, "a greater quantity, amount, or number," in Old English. More and more "larger and larger amounts" is from 12c. More or less "in a greater or lesser degree" is from early 13c.; appended to a statement to indicate nearness but not precision, from 1580s. The more the merrier "the larger the company the greater the enjoyment" is from late 14c. (þe mo þe myryer).
representing African-American vernacular pronunciation of more, by 1902; it was an acceptable variant form of more in the Middle Ages and has roots in Old English; see more.
1749, "two-edged, heavy broadsword of ancient Scottish Highlanders," from Gaelic claidheamh mor "great sword," from claidheb "sword" (compare Welsh cleddyf), which is possibly from a PIE root *kel- "to strike" (see holt) + mor "great" (compare Welsh mawr; see more).
An antiquarian word made familiar again by Scott's novels. It was sometimes applied inaccurately to 16c.-18c. one-handed basket-hilted broad swords. Modern military application to a type of pellet-scattering anti-personnel mine is first attested 1962.
Old English mast "greatest in number, amount, or extent; largest," earlier mæst, from Proto-Germanic *maistaz (source also of Old Saxon mest, Old Frisian mast, Old Norse mestr, Dutch meest, German meist, Gothic maists "most"), superlative form of Proto-Germanic *maiz, root of Old English ma, mara (see more). Used in Old English as superlative of micel "great, large" (see mickle), hence, in later use, superlative of much. The vowel has been influenced by more.
Original sense of "greatest" survives in phrase for the most part (mid-14c.; late Old English had þa mæste dæl). Slang the most meaning "the best, extremely good" is attested from 1953. Also used as an adverb in Old English and in late Old English as a noun, "the greatest or greater number." The sense of "greatest value or advantage" in the phrase make the most of (something) is by 1520s. Related: Mostly.
Double superlative mostest "greatest amount or degree" is by 1849 in U.S. Southern and African-American vernacular. The formula for victory in battle attributed to famously unschooled Confederate Lt. Gen. Nathan Bedford Forrest is first attested (1886) as Git thar the fastest with the mostest men.
From 15c.-17c. English also had mostwhat "for the most part," mostwhen "on most occasions," mostwhere "in most places."