someone who assists a priest or minister in a liturgical service; a cleric ordained in the highest of the minor orders in the Roman Catholic Church but not in the Anglican Church or the Eastern Orthodox Churches
being of crucial importance; "a pivotal event"; "Its pivotal location has also exposed it to periodic invasions"- Henry Kissinger; "the polar events of this study"; "a polar principal"
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"
an anatomical structure used as a point of origin in locating other anatomical structures (as in surgery) or as point from which measurements can be taken
a mark showing the boundary of a piece of land
an event marking a unique or important historical change of course or one on which important developments depend; "the agreement was a watershed in the history of both nations"
the position of a prominent or well-known object in a particular landscape; "the church steeple provided a convenient landmark"