Agua fresca ("fresh water" in Spanish) is a Mexican non-alcoholic drink made by blending fresh fruit, and sometimes flowers or seeds, with water and a sweetener, then straining out the solids. It has roots in pre-Columbian Mesoamerican traditions of blending fruit, herbs, and flowers with water.
Popular varieties include watermelon, pineapple, cantaloupe, hibiscus (jamaica), tamarind, and horchata (a rice-based version). It's typically sweetened with sugar, honey, or agave nectar, served chilled or over ice, and often paired with spicy Mexican dishes as a cooling counterpoint. It differs from a fruit juice or smoothie in that it's diluted with water and strained, giving it a lighter body than either.