Two almost totally different types of bikes, teach. Sport-tourers are basically a sportbike style with hard or soft bags set up for longer distance touring and still able to romp the twisty paved bits. See FJR, ST1300, Concours, BMW RT, Ninja 1000, etc. Adventure bikes are the bigger dirt road and two track capable bikes like the Tenere, 1200GS, KLR, XR650 among others with luggage capability. Lots of ground clearance, highway capable tires, upright seating and the ability to eat miles. Some of us blur the lines to ride dirt roads and two track with sport-tourers and some adventure bikes do cross country real well.