Introduction
The fifth declension is a small group of feminine nouns.
There are no adjectives in the fifth declension.
The typical ending of a fifth declension noun is -i- in front of Nom.Sg. -es.
Some examples of fifth declension nouns are:
dies, ei f-day
dosis pro die (daily dose)
facies, ei f-face, surface
series, el f-series, row
superficies, ei f-surface
species, ei f-species, pl. t. -tea
One of the most common nouns in Latin, res (thing), is found in the fifth declension.
"Res" is where English gets the word "republic," which literally means "public thing" (res publica).