Bill is looking for some answers:
>can someone define these or point me towards the 
>appropriate reference please?

Have a look at Scott Post's great site:

http://members.home.net/sepost/woodwork.html

Go to planemaking, then look at the panel fielder.
In the diagram below it with the surfaces identified
with angles:

50d = bed
70d = wear
65d = breast

Hope this helps.
Louis Michaud