Meaning

noun (law) the privilege of using something that is not your own (as using another's land as a right of way to your own land)

noun the act of reducing something unpleasant (as pain or annoyance)

originFrom Anglo-Norman aisement, easement, eisement, esament, esement, and Middle French aisement (“comfort, convenience, ease, facility, opportunity; a benefit, relief; a right to use land, a thing, etc.; a privy”), from aisier (“to put at ease; to facilitate”) + -ment (“-ment, suffix forming nouns, usually the action or state resulting from verbs”).

Etymology from Wiktionary, CC BY-SA 3.0