mor’-o, too-mor’-o: Two words are used in the Old Testament in this meaning: boqer, which properly means "dawn," or "morning," and machar, properly the same, but used for the next morning and hence, "tomorrow," like the German morgen. The derivative mo-chorath, is "the following day," "all the next day," especially after yom ("day"), but usually coupled with a noun following, as in Le 23:11, mochorath ha-shabbath "day after the Sabbath." It is also used adverbially for "on the morrow," as in Ge 19:34.
In the Greek of the New Testament we find aurion (Mt 6:34, etc.), commonly used, but hexes, also occurs (Ac 25:17 the King James Version, where the Revised Version (British and American) renders more exactly "the next day"); epaurion, is "on the morrow" (Ac 10:9,23,24).