Hosanna means please save.
Hosanna is a liturgical word in Judaism and Christianity. In Judaism, it is always used in its original Hebrew form, Hoshana.
"Hoshana" (הושענא) is a Hebrew word meaning please save or save now. In Jewish liturgy, the word is applied specifically to the Hoshana Service, a cycle of prayers from which a selection is sung each morning during Sukkot, the Feast of Booths or Tabernacles. The complete cycle is sung on the seventh day of the festival, which is called Hoshana Rabbah (הושענא רבא, "Great Hosanna").