meaning

[duffy66]

were does we are rooting for you come from

[Quizmonster]

It started as slang in the USA, especially among baseball fans, in the late 19th century, meaning to cheer on a team. It doesn't appear to have much connection with any of the basic meanings of the word 'root'.

There was another word/phrase often used by Americans, though I haven't heard it for many years, and that was "rootin'-tootin'". This was a form of praise, as in: "It was a rootin'-tootin' party!" Presumably the idea there was that it was a party that deserved cheers and the blowing of trumpets!