In reply to Archibald: Big wall will generally speaking be a route which will take a very long day, or multiple days and be of a consistently high standard of climbing, typically with a minimum grade of VSish, and with many pitches graded above this. Usually it will be exclusively rock climbing although because of their size you may find snow and ice on them in certain conditions, or always if their location (eg Baffin Island) is such that it would be normal. Europe has many, for example the Dolomites has routes of 1000m climbing and more, which is consistent with American style. However where they differ is that generally speaking european big walls will be climbed free (with the odd tug on gear) and at speed, rather than with prolonged pitches of aid and over multiple days, although there are American big wall style routes here too, for example on Monte Qualido in the Mello Valley, or Norway on Kjerag and Troll wall. In the dolomites there are also bigwall sized routes at a much more modest grade, although where it stops being an alpine rock route and a big wall is pretty blurred and to be honest inconsequential. To my mind if you would struggle to climb it in a day then its a big wall!
