The "eight glasses" concept refers to the common recommendation to drink eight 8-ounce glasses of water each day, totaling about 2 liters or half a gallon. This guideline is often cited to promote proper hydration, which is essential for various bodily functions, including digestion, circulation, and temperature regulation. While the "eight glasses" rule is a popular guideline, individual hydration needs can vary based on factors such as age, activity level, and climate. Some people may require more or less water, and other beverages and foods can also contribute to overall fluid intake.