The Collaborative International Dictionary of English v.0.48:
Necessity \Ne*ces"si*ty\, n.; pl. Necessities. [OE. necessite,
F. n['e]cessit['e], L. necessitas, fr. necesse. See
1. The quality or state of being necessary, unavoidable, or
absolutely requisite; inevitableness; indispensableness.
2. The condition of being needy or necessitous; pressing
need; indigence; want.
Urge the necessity and state of times. --Shak.
The extreme poverty and necessity his majesty was
3. That which is necessary; a necessary; a requisite;
something indispensable; -- often in the plural.
These should be hours for necessities,
Not for delights. --Shak.
What was once to me
Mere matter of the fancy, now has grown
The vast necessity of heart and life. --Tennyson.
4. That which makes an act or an event unavoidable;
irresistible force; overruling power; compulsion, physical
or moral; fate; fatality.
So spake the fiend, and with necessity,
The tyrant's plea, excused his devilish deeds.
5. (Metaph.) The negation of freedom in voluntary action; the
subjection of all phenomena, whether material or
spiritual, to inevitable causation; necessitarianism.
Of necessity, by necessary consequence; by compulsion, or
irresistible power; perforce.
Syn: See Need.