Nouns are words that denote people, animals, things, places, ideas, and feelings. Because of their significance, nouns are divided into common and proper nouns.
Luis - Luis (proper)
mesa - table (common)
alegría - happiness (common)
oro - gold (common)
Common nouns designate all beings from the same kind.
perro - dog
bebé - baby
Proper nouns designate a specific being, distinguishing it from the rest of its kind.
Agudo - Agudo (a specific dog)
José - José (a specific boy)
In Spanish, gender and number are applied to nouns. The genders in Spanish are masculine and feminine. Generally if a noun ends in:
-o it is masculine
-a is feminine
el niño - the boy
In this example the noun "niño" names a boy.
la niña - the girl
In this example the noun "niña" names a girl.
Number refers to singular and plural.
Spanish nouns also distinguish between singular and plural.
The general rule is to add "-s" to the noun in singular.
una mesa - one table
tres mesas - three tables
If the singular noun ends in "-z" we do its plural en "-ces".
Tengo un pez. - I have a fish.
Tengo tres peces. - I have three fish.
When the singular noun ends in "-s" and it is formed by only one syllable, we add "-es" to form the plural. This rule also applies to nouns of more than one syllable ending in "-s" and with the accent in the last syllable.
No tengo compás. - I do not have a compass.
Yo tengo dos compases. - I have two compasses.
Nouns ending in "-i" with "tilde" or in "-y" do their plural by adding "-es".
el rey - the king
los reyes - the kings
un Israelí - an Israeli
dos Israelíes - two Israelis