The hymn O Salutaris Hostia is commonly sung at Benediction of the Blessed Sacrament, along with Tantum Ergo. There are at least seven plain chant melodies for O Salutaris Hostia, of which this is number I. There are also at least a couple of metrical tunes for this hymn.
Latin nouns and adjectives, as well as verbs, take different forms, mainly in their endings, which indicate their grammatical role, which is indicated in English mainly by word order. Consequently, the word order in Latin can be more freely arranged than in English. If English poets sometimes put words in a strange order to fit the meter and rhyme, Latin poets do even more so!
O(O) salutaris(wholesome, saving) Hostia(sacrificial victim),
salutáris fundamentally means healthy, wholesome, beneficial; it comes from the word salus, meaning health, welfare, life, safety. So in this context it could be translated “saving.”
Quae(which, who) caeli(of heaven) pandis(you open) ostium(door, entrance),
The -i ending in caeli tells us that this form of caelum (heaven) means of heaven. Consequently, caeli and ostium go together in meaning, although they are separated by the verb pandis, and we have caeli ostium = door of heaven.
pandis is the “you” (singular) form of the verb which appears in dictionaries (in the “I” form, as all verbs do) as pando: to open, spread out, stretch. So, “opening wide” in the poetic translation.
Bella(wars) premunt(they press) hostilia(hostile),
The -a endings here indicate that bella and hostilia go together: so we have bella hostilia = “hostile wars.”
premunt is the “they” form of the verb which appears in the dictionary as premo: to press, squeeze.
Da(give) robur(strength), fer(bring, carry) auxilium(help, aid).
robur primarily refers to very hard wood, especially oak; secondarily, it means hardness, strength. So we can think of it as the strength of oak wood.
The first verse, then, may be literally translated as “O saving victim Who open the gate of heaven, hostile wars are pressing; give strength, grant help.”*
Note the three sound-alike words in the Latin verse: Hostia, ostium, hostilia.
Uni(one) trinoque(and three) Domino(to the Lord)
Sit(let there be) sempiterna(everlasting) gloria(glory):
Qui(who) vitam(life) sine(without) termino(end)
Nobis(to us) donet(let him give) in(in) patria(fatherland, native land, own country).
This verse is more straightforward: “To the One and Triune Lord may there be eternal glory: may He give us in the fatherland life without end.”*
Gregory Weber, 2020 March 7
*Literal translations from The Parish Book of Chant, ©2012 CMAA, Creative Commons Attribution 3.0.