An omer is a measure of grain, in this case, barley. In the days of Temple worship, we were to bring the first sheaf of barley to the Temple, followed by other items, as a sacrifice (Leviticus 9–14).
Whenever I'm asked if the Jewish holidays are coming early or late this year, I promptly answer that they'll be coming on time. And that's partially true. Rosh Hashanah will always arrive on the first day of the Jewish month of Tishrei just as Hanukkah will always begin on the 25th of Kislev.
In the game “Truth-or-Dare,” I choose “truth” nearly every time. I’m not much of a dare-taker. Thus, if you and I were playing “Special Edition Truth-or-Dare: High Holy Days,” I would confess that the prayer Avinu Malkeinu provides me with both my second-favorite liturgical moment and my second-greatest pet peeve of the year’s liturgy. (Note: Even though I may have to repent for it, I will leave you in suspense about my favorite liturgical moment and my greatest liturgical pet peeve. Also, “Special Edition Truth-or-Dare: High Holy Days” is fictional, although I hereby declare copyright in the event Mattel or Hasbro comes knocking at my door.)