(1) (Old Testament) Adam's wife in Judeo-Christian mythology: the first woman and mother of the human race; God created Eve from Adam's rib and placed Adam and Eve in the Garden of Eden
(2) The day before
"He always arrives on the eve of her departure"
(3) The latter part of the day (the period of decreasing daylight from late afternoon until nightfall)
"He enjoyed the evening light across the lake"
(4) The period immediately before something
"On the eve of the French Revolution"