Farming
Middle English: from Old French ferme, from medieval Latin firma ‘fixed payment’, from Latin firmare ‘fix, settle’ (in medieval Latin ‘contract for’), from firmus ‘constant, firm’; compare with firm2. The noun originally denoted a fixed annual amount payable as rent or tax; this is reflected in farm (sense 3 of the verb), which later gave rise to ‘to subcontract’ (farm (sense 2 of the verb)). The noun came to denote a lease, and, in the early 16th century, land leased for farming. The verb sense ‘grow crops or keep livestock’ dates from the early 19th century.
wiktionary
farm + -ing
etymonline
farming (n.)
1590s, "action of farming out, practice of letting or leasing taxes, etc., for collection," verbal noun from farm (v.). Meaning "business of cultivating land, husbandry" is attested by 1733.
