How to remember Spanish noun gender

Spanish nouns have grammatical gender, usually masculine or feminine. The words around them change to match: el libro rojo, la mesa roja. When you call a table feminine, you are describing its grammar. You are saying nothing about the object.

Endings are useful clues, but you cannot tell every noun’s gender from them. Learn the word with enough information to use it in a phrase.

Use endings as a starting point

Many nouns ending in -o are masculine, and many ending in -a are feminine. Common groups such as la información, la decisión, la ciudad and la libertad are also useful to recognise.

Do not turn those examples into a claim that every word with a similar ending must be the same. La mano, el día, el problema and el mapa are familiar counterexamples to the simplest -o/-a rule.

Endings are useful clues. Check the gender when you learn a noun, and keep it with an example such as la mano derecha.

Learn a phrase with the noun

Instead of saving only problema, save el problema or un problema difícil. For mano, in la mano derecha you have both the noun and an adjective that matches it.

With a short phrase you practise the choice you will need to make. Use different examples later so you do not depend on one memorised combination.

Abbreviations often have the gender of their longer forms: la foto from la fotografía, and la moto from la motocicleta. Some nouns have regional variation, so do not assume every disagreement between two sources is an error. These cases are set out separately in the RAE’s account of noun gender.

Why el agua is feminine

Agua is feminine. Immediately before a feminine singular noun beginning with stressed a or ha, the definite article is commonly el: el agua, el águila, el hacha.

The other agreement remains feminine: el agua fría, esta agua, las aguas. With a word between article and noun, use la: la misma agua.

The RAE explains this use of el as a historical form of the feminine article. It is not evidence that the noun has become masculine, or a general ban on two a sounds meeting. La arena is correct because the initial a is unstressed.

For these nouns, an adjective or an explicit gender note is more informative than the singular article alone.

Gender can distinguish meanings

Learn some pairs with their meanings:

Masculine	Feminine
el capital: financial capital	la capital: a capital city
el cura: a priest	la cura: a cure
el orden: order or arrangement	la orden: an instruction or command
el frente: a front	la frente: a forehead

Other words for people have the same form, and only the determiner changes: el estudiante, la estudiante.

Check agreement in a complete sentence

Try Este problema es difícil and Esta pregunta es difícil. The demonstrative changes; difícil does not. Some adjectives have one form for both genders, while others change: español/española, trabajador/trabajadora.

If you make a gender error, check the noun and the words that match it. Then practise a corrected phrase and revisit it later. You find more examples by reading, but you can also give recurring difficulties direct attention.