- the act or process of altering; the state of being altered: Alteration will improve the dress.
- a change; modification or adjustment: There has been an alteration in our plans.
- an adjustment, change, or modification
- the act of altering or state of being altered
late 14c., “action of altering,” from Old French alteracion (14c.) “change, alteration,” and directly from Medieval Latin alterationem (nominative alteratio), noun of action from past participle stem of Late Latin alterare (see alter). Meaning “change in character or appearance” is from 1530s; that of “change in ready-made clothes to suit a customer’s specifications” is from 1901. Related: Alterations.