calvaria

Origin

By the standard Latin plural inflection -a for Latin nouns ending in -um (second declension). The word calvarium was a New Latin coinage from earlier Latin calvaria, and English naturalized it and its plural form intact via unadapted borrowing, as well as allowing a regularized English plural, calvariums; it also did the same thing with calvaria, calvariae, calvarias (first declension), as well.