In reply to yoshi.h:
Route- any climbing traditionally requiring a rope?
Problem- A boulder problem. Could be used to desribe a specific part of a pitch?
Bloc- Used interchangebly with Problem?
Line- Used to describe the actual position of any of the above?
Other terms:
Boulder (pretty self explanatory).
Pitch- Used to describe a specific pitch on a multi-pitch route. Or sometimes just a single pitch?!
Rig- If you are american?