One of the eight parts of speech, adjectives are a type of modifier; that is, they modify or describe nouns in a certain way, letting you know the size, shape, weight, color, nationality, or any of a myriad other possible qualities of nouns.
The Spanish definite article has to agree in gender and number with the noun it modifies, and it doesn’t always correspond to an article in other languages.
Demonstrative pronouns (this one, that one, the one[s], these, those) refer to a previously-mentioned noun in a sentence. Spanish demonstrative pronouns are more complicated than their English counterparts, because there are three different sets and because they must agree in gender and number with the noun they replace.
In Spanish, suffixes called diminutives can be added to nouns, adjectives, adverbs, and names to indicate smallness, as well as other ideas such as affection, humor, pity, irony, or ridicule. In this way, you can say that something is little without adding an adjective like pequeño to indicate smallness or querido to indicate affection.
Qué, cuál, and cuánto are Spanish interrogative adjectives. An adjective is a word that modifies a noun, and interrogative means questioning, so interrogative adjectives are adjectives used to ask the questions "what," "which," and "how much/many."
Possessive adjectives are the words used in place of articles to indicate to whom or to what something belongs. Their usage is similar to English, but there are some differences in form.
Like English nouns, most Spanish nouns have singular and plural forms. In addition, Spanish nouns referring to people and animals often have different masculine and feminine forms, which means that these nouns can have up to four forms.