Nouns: Nombres

Masculine Nouns
The majority of the nouns ending in -o are masculine: libro, curso, and perro.
(There are some exceptions: la mano)

Feminine Nouns
The majority of the nouns ending in -a are feminine: mesa, lengua, and cámara.
(There are some exceptions: el día, el mapa)

Note: Every noun in spanish has a gender.
Nouns that end with -e can be for male or female, the article deturmines the gender.

Singular & Plural
If the noun ends in a vowel, add -s:

If the noun ends in a consonant, add -es:

If the noun ends in -és or -ón , then add -es, it looses the accent:

If the noun ends in -z, it changes into -c then add -es:

If the noun ends in -es and has more than one syllable, the noun does not change: (The article signifies that the noun is plural)