Invariable Nouns in Spanish

Quick Answer

An invariable noun, or sustantivo invariable, is a noun that does not change to reflect gender or—in some cases—number. The article used before the invariable noun indicates the gender or number of the noun.

In Spanish, sustantivos invariables (invariable nouns) are nouns that do not change to reflect a masculine or feminine form or—in some cases—a singular or plural form.

What does this mean? One example of an invariable noun is estudiante(student). Let’s look at how we modify estudiante depending on the number and gender of students we're talking about:

Number	Masculine	Feminine
singular	el^ estudiante	la^^ estudiante^
plural	los^ estudiantes	las^^ estudiantes^

In the singular, the only thing that changes about estudiante is the gender of the article that accompanies it.

Estudiante is not invariable in number, just in gender. This means that the plural form of the noun does take the s in the plural.

Need to review articles in Spanish? No problem! Check these articles about articles out:

Indefinite Articles in Spanish

Using the Indefinite Article in Spanish

Definite Articles in Spanish

Using the Definite Article in Spanish

Invariable Nouns in Spanish: Gender

Let’s check out some more Spanish nouns that do not vary in gender. In this case, you will have to change the gender of the article to reflect the gender of the person (or animal) the noun is referring to.

Spanish	English
agente	agent
antagonista	antagonist
artista	artist
atleta	athlete
auxiliar	assistant
ayudante	assistant
bajista	bass player
bebé	baby
cantante	singer
cascarrabias	grouch
cliente	customer
cónyuge	spouse
dentista	dentist
especialista	specialist
estudiante	student
finalista	finalist
guitarrista	guitar player
intérprete	interpreter
joven	young person
modelo	model
panelista	panelist
patriota	patriot
personaje	character
pianista	pianist
profesional	professional
responsable	person in charge
salvavidas	lifeguard
testigo	witness
violinista	violinist
vocalista	singer

examples
El dentista de esta ciudad, el doctor García, y la dentista del pueblo de al lado, la doctora Miño, se unieron y establecieron una clínica odontológica aquí. The dentist from this city, Dr. Garcia, and the dentist from the next town over, Dr. Miño, have joined forces and created a dental practice here.
Una salvavidas estaba sentada en su silla y un salvavidas estaba en la playa cuando llegó la tormenta. One lifeguard was in the chair and one lifeguard was on the beach when the storm arrived.
No, está equivocado; la señora Rivas es la responsable de esta clase, no el señor Rojas. Él es el responsable del otro curso. You're wrong; Mrs. Rivas is the person in charge of this class, not Mr. Rojas. He's the person in charge of the other course.

Invariable nouns can get tricky. Read more about other tricky nouns in Spanish in this article.

Invariable Nouns in Spanish: Number

There are also nouns that do not change to reflect number. In this case—just like with gender—the only change is in the article that accompanies the noun. Here are examples of nouns that have the same singular and plural forms.

Spanish	English
análisis	analysis
crisis	crisis
dosis	dose
ex	ex
jueves	Thursday
lunes	Monday
martes	Tuesday
miércoles	Wednesday
oxímoron	oxymoron
parabrisas	windshield
parachoques	bumper
paraguas	umbrella
sacacorchos	corkscrew
saltamontes	grasshopper
síntesis	summary
tórax	thorax
trabalenguas	tongue twister
viernes	Friday
virus	virus

Let’s look at how these nouns work in context.

examples
El enfermero nos comentó que debemos lavarnos bien las manos para matar los virus que tenemos en ellas. The nurse told us that we should wash our hands well to kill the viruses that we have on our hands.
El granizo rompió todos los parabrisas de los coches que estaban aparcados aquí. The hail broke the windshields of all the cars that were parked here.
Debes tomar todas las dosis de tu antibiótico. De no hacerlo, puedes contribuir al desarrollo de la resistencia a los antibióticos. You should take all the doses of your antibiotic. If you don’t, you could contribute to the development of antibiotic resistance.