1. Nouns and Gender
Russian nouns have three genders: Masculine, Feminine and Neuter.
You can see which gender the noun is by looking at the ending in the nominative case.
Masculine nouns end in consonants or й:
адрес – address
брат – brother
взрослый – adult
Feminine nouns end in –а, –я, or –ия:
книга – book
аллея – avenue
биология – biology
Neuter nouns end in –е, –о, or –ие:
животное – animal
лето – summer
курение – smoking
There are a few masculine nouns that end in –a/я, such as мужчина (man), дедушка (grandfather), дядя (uncle), or diminutive forms of masculine proper names, like Вася, Андрюша, and so on.
Neuter nouns ending in –о, –е or –и that are direct imports from foreign languages, such as кино, кафе or такси, do not decline (do not change the endings).