"Flavor" is the name used for the different types of quark and the different types of lepton. The six flavors of quarks are up (u), down (d), strange (s), charm (c), bottom (b), and top (t), in increasing order of mass. These govern the weak interaction dynamics of the quarks, the flavors being essentially the 'weak charges' on the quarks.

 

The flavors of charged leptons are the electron, muon, and tau, again in increasing order of mass. For each charged lepton flavor there is a corresponding neutrino flavor.