Definite and Indefinite Articles

The difference between definite articles and indefinite articles can be observed in the following two sentences:

• I want a dark blue BMW. (a particular, or definite car)
• I want a car. (an indefinite car)

The difference between the definite and indefinite articles is the difference between talking about a specific car, or any car.

• the car
• a car

In English, the definite article is the word "the" regardless of whether the noun it introduces is singular or plural.

• the car
• the cars

In Spanish, the definite article has 4 forms, depending on whether the noun is masculine, feminine, singular or plural.

• el perro
  the male dog

• los perros
  the male dogs

• la perra
  the female dog

• las perras
  the female dogs

In English, the indefinite article is the word "a," "an," or "some."

• a cookie
• an apple
• some books

In Spanish, the indefinite article has 4 forms, depending on whether the noun is masculine, feminine, singular or plural.

• un gato
  a male cat

• unos gatos
  some male cats

• una gata
  a female cat

• unas gatas
  some female cats

The 4 forms of the indefinite article are:

un - masculine singular
una - feminine singular
unos - masculine plural
unas - feminine plural 

Here are the definite and indefinite articles together:

el, un - masculine singular
la, una - feminine singular
los, unos - masculine plural
las, unas - feminine plural 

Each of the following has a different meaning:

• el gato
  the male cat

• los gatos
  the male cats (or a mixed group)

• la gata
  the female cat

• las gatas
  the female cats

• un gato
  a male cat

• unos gatos
  some male cats (or a mixed group)

• una gata
  a female cat

• unas gatas
  some female cats

"Un" and "una" can mean "one," "a," or "an."

• un libro
  one book, a book

• una pluma
  one pen, a pen

• una manzana
  one apple, an apple