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.
Entries linking to farming
farm v.
mid-15c., "to rent (land)," from Anglo-French fermer, from ferme "a rent, lease" (see farm (n.)). The agricultural sense is from 1719. Original sense is retained in to farm out.