Noun gender

All nouns in Bulgarian have a gender which determines how adjectives and pronouns act around them and also which third person personal pronoun the noun can be replaced with. There are 3 noun genders - masculine, feminine and neuter.

Rules to help you identify the gender

When the noun is the name for a type of person or animal with a known gender the grammatical gender matches the real one.
A person's name matches their own gender.
Usually nouns ending in a consonant are masculine.
Usually nouns ending in -а or -я are feminine.
Usually nouns ending in -е or -о are neuter.
Month names are masculine.
The above is a huge oversimplification to help you kind of guess right most of the time but it doesn't hurt to use a dictionary (мъжки род=masculine, среден род=neuter, женски род=feminine) and get a feel for it since nobody actually remembers rules like that

Masculine examples

дядо, баща, февруари, вол, балкон, покрив, картоф

(Translations: grandpa, father, February, ox, balcony, roof, potato)

Feminine examples

баба, леля, майка, гръмотевица, лампа, кола, сутрин, вечер, хубост, кост

(Translations: grandma, aunt, mother, thunder, lamp, car, morning, evening, beauty/prettiness, bone)

Neuter examples

дете, момче, момиче, петно, перде

(Translations: child, boy, girl, stain, curtain)