What does -ae mean?

-ae meaning in Etymology Dictionary

periodic plural suffix of terms closing in -a, nearly all of which, in English, are from Latin nominative fem. single nouns, that Latin form their particular plurals in -ae. But plurals in -s had been founded early in English for most of those (eg concept, arena) and several have entered more than since. Now it is really not possible to require purity one-way or even the various other without reproduction monsters.