easement

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act of easing or the condition of being eased.
• noun Something that affords ease or comfort.
• noun Law A right to make limited use of another's land, such as a right of way.

from The Century Dictionary.

• noun That which gives ease, relief, or assistance; convenience; accommodation.
• noun In law, a right of accommodation in another's land; such a right in respect to lands—as that of passage, or of having free access of light and air—which does not involve taking anything from the land; more specifically, such a right when held in respect to one piece of land by the owner of a neighboring piece by virtue of his ownership of the latter.
• noun In carpentry, same as ease-off.

from the GNU version of the Collaborative International Dictionary of English.

• noun That which gives ease, relief, or assistance; convenience; accommodation.
• noun (Law) A liberty, privilege, or advantage, which one proprietor has in the estate of another proprietor, distinct from the ownership of the soil, as a way, water course, etc. It is a species of what the civil law calls servitude.
• noun (Arch.) A curved member instead of an abrupt change of direction, as in a baseboard, hand rail, etc.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun law Legal right to use another person's property, generally in order to cross a part of the property, or to gain access to something on the property.
• noun archaic Relief, easing.
• noun archaic, euphemistic The act of relieving oneself: defecating or urinating
• noun architecture A curved member instead of an abrupt change of direction, as in a baseboard, handrail, etc.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

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