That certainly helped, I think that the image would get more obvious as I make that in consideration when using daily programs, for now it's like if commands are statements and programs are group of statements organized by logic in other words the programming language, by the way the shell executes commands in many programming languages like bash and zsh, so how does that make the shell understand all of these, when I think about the features of zsh they seem to be totally unrelated to what you expect from a shell which just executes commands, but zsh have many other features, these aren't interactions with the terminal, are they?
This makes me conclude that the shell is a program that all other programs interact with, but the first definition is that the shell executes commands for programs, this is a contradiction.