adj.
1.absolutely necessary
2.basic and fundamental
3.of the greatest importance
4.being or relating to or containing the essence of a plant etc
5.applying to essential legal principles and rules of right
6.absolutely required and not to be used up or sacrificed essential n.
1.anything indispensable
Idiom of the Day
on (someone's) doorstep
in someone's care, as someone's responsibility
The responsibility for feeding the extra staff suddenly arrived on my doorstep.