The acronym HTTP stands for HyperText Transfer Protocol, which is the foundation for data communication on the web. It is a protocol used for transmitting hypertext via web browsers, allowing users to access and interact with websites. HTTP governs how messages are formatted and transmitted, ensuring that requests and responses between clients and servers are understood efficiently. The introduction of HTTPS, or HTTP Secure, enhances this protocol by adding a layer of security through encryption, protecting data during transmission and ensuring user privacy in online communications.