c. 1200, "to repair" (clothes, a tool, a building), "remove defects" (from something broken, defaced, deranged, or worn), from a shortened form of Old French amender "correct, set right, make better, improve" (see amend). Meaning "to put right, atone for (faults and errors), amend (one's life), repent" is from c. 1300. Intransitive sense of "to grow better, improve" is from late 14c. Related: Mended; mending.
early 14c., "recompense, reparation," a shortened form of amends. Sense of "a remedy, cure" (now obsolete) is from mid-14c., from mend (v.). Meaning "act of mending; a repaired hole or rip in fabric" is from 1888. Phrase on the mend "on the path to recovering from sickness, improving in condition" is attested by 1802.