vs
QUICK ANSWER
"Dos" is a form of "dos", an adjective which is often translated as "two". "Un" is an indefinite article which is often translated as "a". Learn more about the difference between "un" and "dos" below.
un(
oon
)An indefinite article is a word that indicates that a noun is not specific (e.g., a girl).
1. (singular)
b. an (before vowel sound)
Tienen una vieja cámara que todavía funciona.They have an old camera which is still working.
dos(
dohs
)An adjective is a word that describes a noun (e.g., the big dog).
A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).
2. (number)