A confession; A defense of one's faith, or a confession of guilt.(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "confessio" in a sentence
"Christ before men at the cost of their lives -- hence the name confessio was applied to their last resting-place, when, as happened frequently from the fourth century, an altar was erected over it."
"(One can just see the confessio beneath the Altar, where the relics of St. Sabina are found)"
"I thought it fitting to share with you an image of St. Lawrence from the basilica dedicated to him in Rome, St. Lawrence outside the Walls, as well as the confessio beneath the high altar of the same basilica, where his relics are kept and venerated."