Romanian plural nouns

In general, masculine nouns end in i, feminine nouns in e, or i and neuter in e, or uri.

dog (masculine) câine dogs câini
cat (feminine) pisică catspisici
beer (feminine) bere beers beri

The above rule, is very, very general and there are various possible changes in the plural.

Masculine nouns may change the final consonant.

child (masculine) copil children copii

Feminine nouns ending in an ă, change the ă to an e.
house (feminine) casă houses case
table (feminine) masă tables mese