Thanks for all the responses. I think Padre gets to wear the laurel in this contest. Now I can see new relationships.

immolatum = sacrifice. It bothered me that to immolate something is to burn it up completely, but now I see that in Latin the concepts of sacrifice and burning had merged.


Hail, hail true body,
born of the virgin Mary,
truly having suffered sacrifice
on the cross on behalf of man.

Whose pierced side
trickled water and blood
be thou for us a foretaste
in the test of death.

pregustatum = foretaste. Of course, a pre-gusto.
esto = be, as in German or French est, meaning is.

Only one word still puzzles me. What's "passum"?