How do we call a hadith which a sahabi has narrated on the authority of another sahabi?

I'm sure that the sahaba were used to remind each other of the teachings of our Prophet (), so it could certainly be that Sahabi A has witnessed the Prophet doing or saying something, while Sahabi B was not present, but heard it through Sahabi A. If Sahabi B now was to transmit this narration to a tabi'i (and so on) what would this hadith be called, is there a specific term for this in the hadith sciences? What if Sahabi B said the Prophet said/did ... (without quoting sahabi A) would that also be called tadlees? (If this would make the answer too long and needs a separate question, maybe one could discuss it in https://islam.stackexchange.com/questions/46975/what-exactly-is-tadlees or I might ask a new question)