A compound word is one word created by adding two words together. In Spanish, compound nouns are often created by attaching the plural form of a noun to the base of a verb. These words always look plural and sometimes even look feminine, but a compound noun is always masculine and is the same in its singular and plural form.
abre (opens) + latas (cans) ---> el abrelatas - the can opener (singular)
or los abrelatas - the can openers (plural)
toca (plays) + discos (records) ---> el tocadiscos - the record player (singular)
or los tocadiscos - the record players (plural)
rasca (scrapes) + cielos (skies) ---> el rascacielos - the skyscraper (singular)
or los rascacielos - the skyscrapers (plural)
Although compound nouns are formed by more than one word, they work as a single word within the sentence. We use compound nouns when a single noun is not clear enough to name a person or object. There are several types of compound nouns in Spanish.
máquina de escribir - typewriter (noun + preposition + verb)
página web - webpage (noun + noun)
sacacorchos - corkscrew (verb + noun)
Compound nouns are also countable nouns, so we can form their plural form. Normally we are going to follow the rules for the plural in the last or in the first component of the compound nouns.
Tengo un girasol. - I have a sunflower.
Tengo dos girasoles. - I have two sunflowers.