plurals

Here are some rules for making Latin or Greek plurals.
Nouns ending in “-a” switch to “-ae” to make the word plural.
alga → algae
larva → larvae
vertebra →  vertebrae
Nouns with an “-um” ending turn into an “-a” ending.
candelabrum →  candelabra
medium →  media
spectrum →  spectra
Words that end in “-is” are swapped to “-es” to make them plural.
paralysis → paralyses
diagnosis → diagnoses
thesis →  theses
Terms that end in “-us” can be made plural using “-i” in place of “-us.”
cactus → cacti
alumnus → alumni
syllabus →  syllabi
However, English has gone its own way, and exceptions abound, less so in the sciences than in everyday usage. That’s English, ever-changing, forcing us to use a dictionary. That’s the beauty of Latin, never-changing. I had the help of wordgenius.