Nouns, Articles and Adjective Agreement

Understanding nouns, articles and adjective agreement is the foundation of Spanish grammar. Every noun in Spanish has a gender (masculine or feminine) and a number (singular or plural), and all articles and adjectives must agree with the noun they describe.

1. Gender of Nouns (El género)

General Rules

Rule	Examples	Exceptions to know
Nouns ending in -o are usually masculine	el libro, el amigo, el colegio	la mano (hand), la foto (photo), la moto (motorbike)
Nouns ending in -a are usually feminine	la mesa, la casa, la chica	el día (day), el mapa (map), el problema, el tema, el sistema
Nouns ending in -ción, -sión, -dad, -tad are feminine	la nación, la televisión, la ciudad, la libertad	—
Nouns ending in -ma (of Greek origin) are often masculine	el problema, el tema, el sistema, el programa	la cama (bed)
Nouns ending in -ista can be either gender	el/la periodista, el/la dentista	Depends on the person

Exam tip: Learn the common exceptions — especially "el día", "el mapa", "el problema", "la mano". These are favourites in grammar-testing questions.

2. Articles (Los artículos)

Definite Articles (the)

	Singular	Plural
Masculine	el	los
Feminine	la	las

Indefinite Articles (a/an, some)

	Singular	Plural
Masculine	un	unos
Feminine	una	unas

Special Rules

el agua (not "la agua") — feminine nouns starting with a stressed "a" or "ha" use "el" in the singular: el agua, el hambre, el águila, el hacha. BUT the noun remains feminine: "El agua está fría" (not "frío").
After negatives, the indefinite article is often dropped: "No tengo hermanos" (NOT "No tengo unos hermanos").
Before professions with ser: "Es médico" (NOT "Es un médico") — unless qualified by an adjective: "Es un buen médico."

3. Plural Formation (El plural)

Ending	Rule	Example
Vowel	Add -s	libro → libros, casa → casas
Consonant	Add -es	ciudad → ciudades, profesor → profesores
-z	Change to -ces	lápiz → lápices, vez → veces
Unstressed vowel + -s	No change	el lunes → los lunes, la crisis → las crisis

4. Adjective Agreement (La concordancia)

Adjectives MUST agree with the noun they describe in gender and number.

Agreement Patterns

Adjective type	Masc. sing.	Fem. sing.	Masc. pl.	Fem. pl.
Ends in -o	alto	alta	altos	altas
Ends in -e	grande	grande	grandes	grandes
Ends in consonant	fácil	fácil	fáciles	fáciles
Ends in -or	trabajador	trabajadora	trabajadores	trabajadoras
Ends in -ista	optimista	optimista	optimistas	optimistas

Position of Adjectives

In Spanish, most adjectives go after the noun (unlike English):

Una casa grande — A big house
Un libro interesante — An interesting book
Los ojos azules — Blue eyes

Some common short adjectives can go before the noun:

buen → un buen amigo (a good friend)
mal → un mal día (a bad day)
gran → una gran ciudad (a great city)
primer → el primer día (the first day)

Exam tip: Adjective agreement errors are heavily penalised. Always check that your adjective matches the noun in gender and number. A common mistake: "una chica simpático" — it MUST be "simpática".

5. Demonstrative Adjectives

	Masculine sing.	Feminine sing.	Masculine pl.	Feminine pl.	English
Near	este	esta	estos	estas	this / these
Medium	ese	esa	esos	esas	that / those
Far	aquel	aquella	aquellos	aquellas	that (over there) / those

Key Vocabulary Summary

Gender rules: -o = masculine, -a = feminine (with exceptions)
Articles: el/la/los/las (definite), un/una/unos/unas (indefinite)
Plural: add -s (vowel), -es (consonant), -z → -ces
Agreement: adjectives match noun in gender and number
Position: most adjectives follow the noun
Demonstratives: este/ese/aquel (and feminine/plural forms)