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"
a wave resulting from the periodic flow of the tides that is caused by the gravitational attraction of the moon and sun
an unusual (and often destructive) rise of water along the seashore caused by a storm or a combination of wind and high tide
an overwhelming manifestation of some emotion or phenomenon; "a tidal wave of nausea"; "the flood of letters hit him with the force of a tidal wave"; "a tidal wave of crime"
showing the wearing effects of overwork or care or suffering; "looking careworn as she bent over her mending"; "her face was drawn and haggard from sleeplessness"; "that raddled but still noble face"; "shocked to see the worn look of his handsome young face"- Charles Dickens
a right reserved exclusively by a particular person or group (especially a hereditary or official right); "suffrage was the prerogative of white adult males"