absolutely required and not to be used up or sacrificed
absolutely necessary; vitally necessary; "essential tools and materials"; "funds essential to the completion of the project"; "an indispensable worker"
being or relating to or containing the essence of a plant etc; "essential oil"
the kitchen area for food preparation on an airliner
(classical antiquity) a crescent-shaped seagoing vessel propelled by oars
a large medieval vessel with a single deck propelled by sails and oars with guns at stern and prow; a complement of 1,000 men; used mainly in the Mediterranean for war and trading