hypertext transfer protocol and hypertext transfer protocol secure. it's the basic network protocol of the modern internet. hypertext can be thought of as being html (hypertext markup language) though other hypertext specifications do exist. hypertext just means documents with links to other documents.

you know how when you copy a url (universal resource location) from your web browser it always has http or https at the start of it? that's because your web browser is connecting to an external server somewhere via the hypertext transfer protocol.

cURL can connext to nearly any server via nearly any standard protocol. it's commonly used for validating connection information and downloading files

It's the protocol most computers use to show websites. In an internet address like https://google.com/, the https:// is the protocol. Different protocols have different features and purposes, but http/https are some of the most common.