A word of joyful acclamation in Hebrew, signifying save now. The people cried Hosanna as Jesus entered in triumph into Jerusalem; that is, they thus invoked the blessings of heaven on him as the Messiah, Matthew 21:9. This was also a customary acclamation at the joyful feast of tabernacles, in which the Jews repeated Psalms 118:25,26.
These dictionary topics are from American Tract Society Bible Dictionary published in 1859. Public Domain, copy freely.
Rand, W. W. "Entry for 'HOSANNA'". "American Tract Society Bible Dictionary".