Amount
Middle English (as a verb): from Old French amunter, from amont ‘upward’, literally ‘uphill’, from Latin ad montem . The noun use dates from the early 18th century.
wiktionary
From Middle English amounten(“to mount up to, come up to, signify”), from Old French amonter(“to amount to”), from amont, amunt(“uphill, upward”), from the prepositional phrase a mont(“toward or to a mountain or heap”), from Latin ad montem, from ad(“to”) + montem, accusative of mons(“mountain”).
etymonline
amount (v.)
late 13c., "to go up, rise, mount (a horse)," from Old French amonter "rise, go up; mean, signify," from amont (adv.) "upward, uphill," literally "to the mountain" (12c.), a contraction of the prepositional phrase a mont, from a (from Latin ad "to;" see ad-) + Latin montem (nominative mons) "mountain" (from PIE root *men- (2) "to project"). Meaning "to rise in number or quality (so as to reach)" is from c. 1300. Simple mount (v.) is not used in the physical senses. Related: Amounted; amounting.
amount (n.)
"quantity, sum," 1710, from amount (v.). As nouns, Middle English had amountance, amountment.