Gender agreement refers to the grammatical rule in many languages where words must match in gender. For example, in languages like Spanish or French, nouns, adjectives, and articles can be masculine or feminine. This means that if a noun is feminine, any adjectives or articles describing it must also be in the feminine form. In Spanish, the word for "girl" is "niña," which is feminine. Therefore, you would say "la niña bonita," meaning "the pretty girl," where "la" and "bonita" agree in gender with "niña." Understanding gender agreement is essential for proper sentence structure and communication in gendered languages.