HOST, HOSPES, a term of mutual relation, applied both to a person who lodges and entertains another, and to the person thus lodged, &c.—The word is formed of the Latin hospes, which some will have thus called quasi hostium or ostium petens; for ostium was anciently written with an aspirate.—Thus the inn-keeper says, he has a good host, in speaking of the traveller who lodges with him: and the traveller, again, says, he has a kind host, in speaking of his landlord.
It must be observed then, that it was the custom among the ancients, when any stranger asked for lodging, for the master of the house, and the stranger, each of them to set a foot on their own side of the threshold, and swear they would neither of them do any harm to the other. It was this ceremony that raised so much horror against those who violated the law or right of hospitality on either side; inasmuch as they were looked on as perjured.
Instead of hospes, the ancient Latins called it hostis; as Cicero himself informs us: though, in course of time, hostis came to signify an enemy; so much was the notion of hospitality altered.
HOST is also used by way of abbreviation for hostia, a victim or sacrifice offered to the Deity. In this sense, host is more immediately understood of the person of the Word incarnate, who was offered up an host or hostia to the Father on the cross for the sins of mankind. See HOSTIA.