Alleluia: What does it mean?

"Beginning with the Easter Triduum as its source of light, the new age of the Resurrection fills the whole liturgical year with its brilliance... Therefore, Easter is not simply one feast among others, but the Feast of feasts... Easter is the Great Sunday. The mystery of the Resurrection, in which Christ crushed death, permeates with its powerful energy our old time, until all is subjected to him." CCC 1168-9

Since Sunday, we have been congratulating Our Lady, as advised by St. Thomas Aquinas, and the Church itself has recommended to us how to do so-- the Regina Coeli.

Queen of heaven, rejoice! Alleluia!

For he whom you did merit to bear. Allelulia!

Has risen as he said. Alleluia!

What a great prayer! Especially, with the addition of the Alleluia, the prayer becomes a prayer of joy and exultation.

But, what does "alleluia" mean? especially now that we repeat it so often, even at the end of Mass?

Alleluia is from "Hallelu-jah". And hallelu is from hallel and hillel which means "praise be to you." And jah or yah refers to Yahweh.

So Alleluia means Praise to you, O God! or Praise the Lord!!! It's the ancient Catholic way of saying what Protestants love to say: Praise the Lord!!!