A Ziplock bag is a type of plastic storage bag that features a resealable closure. It is made from flexible plastic and is designed to keep food and other items fresh by preventing air and moisture from entering. The closure works by sliding a plastic zipper along the top of the bag, creating an airtight seal. These bags come in various sizes and are commonly used for storing food, organizing small items, or packing items for travel. They are convenient, reusable, and often dishwasher-safe, making them a popular choice for both home and on-the-go use.