hosanna in the heights is a term from both Latin and Hebrew, and means "save us, we beg you”, or “I beg you”. Hosanna on high is a prayer to God, and it means: “Save us now, O You who dwell in the highest”.
This expression is very popular in Christianity and Judaism and there are several songs created with this expression.
The term came up at a time in history, which is told in the Bible. It occurred when a crowd expected Jesus to be an earthly king, and the reception they gave him was reminiscent of Solomon's enthronement or Jehu's ascension to the throne of Israel. According to the Bible, more specifically in Matthew 21:8, people immediately took their robes and spread them on the steps. Jesus did not intend to become an earthly king, but rather, he humbled himself and was obedient to the point of death on the cross.
The crowd shouted “Hosanna”, as if repeating the words of Psalm 118:25: “Save us, LORD”! We beg you. It wouldn't be long before the crowd, instigated by the agitators planted there by Jesus' enemies, would shout: "Crucify him."
In English, the expression Hosanna in the heights is translated as "Hosanna in the highest".
See also the meaning of Yeshua.