That is, most often adjectives are used to describe a noun, or distinguish the noun from a group of similar objects. For example, an adjective might describe the color of an object. In Spanish, most adjectives change form, depending upon whether the word they modify is masculine or feminine.
Adjectives also change form depending upon whether the word they modify is singular or plural.
These adjectives have four forms. The correct form of the adjective depends upon the noun it modifies. Notice how the endings of the nouns and these adjectives are similar. To form the plural, simply add -s. To form the plural, add -es.