Nouns are words for naming persons, things, places and animals. In Portuguese, a noun can be either masculine or feminine in gender and singular or plural in number.It is very important to know the gender, otherwise you will not be able to speak the language correctly. The best way to learn the gender of a noun is to memorize it with its definite article.
In general nouns ending in -o as in carro (car) or nouns referring to male persons like amigo (male friend) or animals like gato (male cat) are masculine, and nouns ending in -a as in casa (house) or nouns referring to female persons like amiga (female friend) or animals like gata (female cat) are feminine.
Masculine and Feminine Nouns
o amigo/ a amiga
the male/female friend
o espanhol/ a espanhola
the Spanish guy/lady
o professor/ a professora
the male/female teacher
o inglês/ a inglesa
the English guy/lady
o alemão/ a alemã
the German guy/lady
o pai/ a mãe
the father/mother
Masculine or Feminine Nouns
o colega/ a colega
the male/female colleague
o chefe/ a chefe
the male/female boss
o repórter/ a repórter
the male/female reporter
Nouns used for both male or female persons and animals
a criança
the child
a cobra
the snake
The Definite Article
singular o/ a the
plural os/ as
the
The definite article is used before nouns, countries, continents, rivers, islands, regions, seasons of the year, days of the week, colors, possessive pronouns, parts of the body, titles and even before names in some regions of Brazil.
It specifies the noun and at the same time it indicates its gender and number.The definite article is more frequently used in Portuguese than in English.
o livro
the book
a caneta
the pen 
