adjective

1. that cannot be dispensed with; essential; indispensable the nutriments necessary to life
2. resulting from necessity; inevitable a necessary result
3. 1. that must be done; mandatory; not voluntary
   2. not free to choose; compelled by circumstances a necessary agent
4. inherent in the situation; undeniable; unavoidable from the premises
5. Archaic rendering some essential and intimate service

Etymology: ME < L necessarius < necesse, unavoidable, necessary < ne-, not + cedere, to give way: see cede

noun pl. necessaries -·sar′·ies

1. a necessary thing; thing essential to life, some purpose, etc.: often used in pl.
2. Dialectal a privy or toilet
3. Law those things essential to maintaining a dependent or incompetent in comfort and well-being