The English word “host” possesses a variety of meanings. The word is used frequently in the liturgy and in translations and so it’s important to understand the different nuances.

1) “Host” can refer to a military host of soldiers. This is applied to God as the Lord of hosts, that is, the Lord of the armies of Heaven. This meaning comes from hostis, meaning “army, war-like expedition.”

2) “Host” can refer to the Holy Eucharist as in “Father McGillicuddy placed the host on her tongue.” This meaning comes from the Latin hostia meaning “sacrificial victim.” Christ is the saving victim of God the Father. For example, the beginning of the hymn O Salutaris Hostia means O Saving Victim.

3) “Host” can also refer to someone who provides a party. For example, “Mr. Miller is the host of the party.” Related to this definition is an organism that has a parasite. This meaning comes from the same Latin word hostia from (2) above. The reason for this is that the “host” of a party is the sacrificial victim – he or she pays for everything so that others can enjoy it. A sacrificial victim likewise “pays the price” so that others can benefit.

In the Holy Sacrifice of the Mass we say, “Holy Holy Holy Lord God of Hosts.” Here we are not referring to the round little hosts in the ciborium or on the paten. No, we are referring here to God as Captain of the celestial army of spiritual warfare. Here we invoke God as the Lord of Judgment who arrives with myriads of angels and saints:

And they cried one to another, and said: Holy, holy, holy, the Lord God of Hosts (צְבָא֑וֹת), all the earth is full of his glory (Isaiah 6:3, D-R).

In the Hebrew, God is here called “Lord God of צְבָא֑וֹת” or “Lord God of Sabaoth.” Saboath means “army hosts.” This is also confusing since the word sounds like the word “Sabbath.” Sabaoth means “army hosts,” but sabbath means “seventh day rest.” Two complete different words.

At other times we refer to the “host” as the Holy Eucharist. Christ is the sacrificial victim of the Catholic Church. He paid everything so that the gates of Heaven might be open to us. Christ a “host” in that He provides the Supper of the Lamb as the “host” of the celebration, and Christ is the sacrificial victim or hostia who is immolated for our redemption.

Quick Review:
Hosts = either “army hosts” or “Eucharist” (English word)
Hostia = “sacrificial victim (Latin word)
Hostis = “army hosts” (Latin word)
Sabaoth = “army hosts” (Hebrew word)
Sabbath = “seventh day of rest” (Hebrew word)