It's not slang or jargon. It is informal and colloquial. It means "approximately," "more or less," or "close enough." "What does carob taste like?" "It tastes kind of like chocolate, but it's not going to fool anybody. It's not really like chocolate, and it's not a good substitute." "Now that you point it out, I see it--those rocks do look kind of like a face." "In some ways you can think of an atom as being like a solar system, with the electrons in orbits around the nucleus. But in other ways, once you realize that the electrons can be waves instead of particles, it is not like a solar system at all."

Person A: 'Do you like this shirt?' -> Person B: 'Kind of' -> This means that person B likes the shirt a little bit. Doesn't like it too much, doesn't like it too little. We can also say 'sort of'. ALSO 'a kind of something' is a 'type of something' or a 'sort of something'. A kind of shirt. A type of shirt, a sort of shirt, a style of shirt.

"Kind of" is similar to saying "a bit", "a little" or like "un poco" For example, "I think that he is a bit annoying" "Yo creo que es un poco molesto" Or yes, you can also use it in that context. So when you say that something is a type of something - a type of dog, a type of flower, type of funny phrase, type of song etc For example "That is a kind of dog" "Que es un tipo de perro"

Thank you for your responses! So maybe in spanish "kind of" is like "mas o menos", "algo así" or "casi". Thank you again!

"Kind of" and "sort of" are more slang or vernacular speech. They should not be used in formal writing. - I'm kind of tired => I'm a little bit tired (similar to tired but not exactly the same as tired) - I'm kind of busy right now => I'm a little busy right now. These expressions are sometimes used to "soften" the speaker's tone so he sounds more polite.