Uscita means exit (and equivalent to junction on UK motorways).
A8 means Autostrada 8 (like M8 in UK).
E33 means European Route 33
SS means Strada Statale (equivalent to A road in UK).
The bullseye sign next to Settimo M. means centro, ie the centre of Settimo M. This bullseye sign is commonly used for the centre of towns, so keep an eye out for it.