Articles are small words that precede the substantive (a noun).
Definite article: used to indicate that a thing is unique in some way.
Indefinite article: used to indicate that a thing is not identified as unique.
In Portuguese the article must agree in gender and number with the noun, which means that the definite article o, for example, should precede a singular and masculine (as you could see in the first example – “o carro”). Observe the chart below:
|Articles||Definite – singular /plural||The Indefinite – singular / pluralA / Some|
|Masculine||O / Os||Um / Uns|
|Feminine||A / As||Uma / Umas|