cURL is a command-line tool and library used for transferring data with URLs. It supports various protocols, including HTTP, HTTPS, FTP, and more, allowing users to send and receive data over the internet. Developers often use cURL to test APIs, download files, or automate web requests. The name "cURL" stands for "Client for URLs." It is widely used in programming and web development due to its versatility and ease of use. With cURL, users can perform tasks like submitting forms, retrieving web pages, and managing file uploads, making it an essential tool for many developers.