Erev means evening or sunset — the period from late afternoon through darkness. It appears about 134 times and is central to the biblical reckoning of time: in the Hebrew calendar, each day begins at sunset (erev), so evening precedes morning. The phrase erev v'voker ("evening and morning") appears in the creation account and the Daniel prophecy. The cognate verb arav means to become dark or to pledge/mix.
The biblical day beginning at evening (erev) shapes Israel's entire liturgical calendar — Sabbath begins Friday evening, Passover begins at sunset, Yom Kippur is observed "from evening to evening" (Leviticus 23:32). This rhythm of darkness-before-light is deeply theological: before every divine morning there is an evening of waiting. The "two evenings" (bein ha-arbayim) of Exodus 12:6 (twilight) was when Passover lambs were slaughtered — the very time Jesus died. Evening becomes the hour of sacrifice and redemption.