A terminal is a computer program that lets a person talk to a computer. Think of it like talking to a friend, but instead of using words, you type in commands on the computer keyboard.
Terminal capabilities are all the different things that the computer and the terminal can do together. For example, they can change the color of the text, make the text bigger or smaller, move the cursor around, and run different programs.
Different terminals can have different capabilities, which means they can do different things. Some terminals may only have basic capabilities like typing in commands and showing text, while others may have more advanced capabilities like graphics and special effects.
Programmers and developers use terminal capabilities to make their programs and software work better. They can use the different capabilities to make their programs look better, work faster, and have more features.
So in short, terminal capabilities are all the things that a person can do with a computer program that lets them talk to the computer, and they're used by programmers to make their programs better.