Something that makes life easier or more pleasant.
1) The hotel has every amenity one could want.
2) They're an unhappy, bickering couple who, at least in public, observe all amenities of good behavior.
Middle English amenite, from Latin amoenitat-, amoenitas, from amoenus which means 'pleasant'.
civility, attention, courtesy, formality, gesture, pleasantry
basic, essential, fundamental.