Nouns in Spanish have a gender, either masculine or feminine. Most nouns ending in -o are masculine and most ending in -a are feminine. To make nouns plural, usually add -s to singular words ending in a vowel and -es to words ending in a consonant. Definite articles like el, la, los, and las translate to "the" in English and agree with the gender of the noun. Indefinite articles like un, una, unos, and unas translate to "a/an" or "some" depending on the word.