A DUNS number is a 9-digit business ID number from Dun & Bradstreet. Apple requires you to have one if you want to create an organization developer account for the App Store. See http://blog.metamorphium.com/2012/12/03/apple-duns/
Dun and Bradstreet number (a weird business registration number), Statement of Work, Master Services Agreement
SOW is probably Statement of Work. Dunsno about the others.
What are these abbreviations?