a plural ending of nouns borrowed from Greek and Latin:
phenomena; criteria; data; errata; genera.
a feminine singular ending of nouns borrowed from Latin and Greek, also used in Neo-Latin coinages to Latinize bases of any origin, and as a Latin substitute for the feminine ending - ē of Greek words:
anabaena; cinchona; pachysandra.
an ending of personal names forming feminines from masculines:
< L feminine -a (see -a2), as Claudia, feminine of Claudius
a suffix designating the oxide of the chemical element denoted by the stem: