Anything (such as a piece of furniture, or a software feature) that is built in, not added as an extra.
Being an essential and permanent part of something.
Being an included feature that normally comes as an extra.
Constructed as a non-detachable part of a larger structure.
Something necessary; a requisite; something indispensable.
Something which makes an act or an event unavoidable; an irresistible force; overruling power.
Greater utilitarian good; used in justification of a criminal act.
Indispensable requirements (of life).
The negation of freedom in voluntary action; the subjection of all phenomena, whether material or spiritual, to inevitable causation; necessitarianism.
The condition of being needy; desperate need; lack.
The quality or state of being necessary, unavoidable, or absolutely requisite.