# Does the renormalisation group flow actually involve a group? [duplicate]

I've come across the notion of a renormalisation group flow in a number of places; for example, in Dr. Tongs lecture notes in QFT:

it will turn out that that the possible interactions in QFT will be governed by a few basic principles: locality, symmetry & renormalisation group flow (the decoupling of short scale phenomena from physics at larger scales)

The wiki article whilst informative, doesn't actually say; if a group is not involved, then presumably some group like thing is; also what exactly is 'flowing' in the renormalisation group flow?