A cloud storage bucket is an online container used to store and organize files, such as documents, images, and backups, on cloud computing platforms like Amazon S3 or Google Cloud Storage. Buckets make it easy to upload, access, and share data from anywhere with an internet connection. They can be configured as private, restricting access to authorized users, or set to public, allowing anyone to view or download the contents. Proper configuration is important to prevent unauthorized access and protect sensitive information.