Problem Solved

Thanks, Nat & Gretchen!

The reason I was curious about the difference between astonish and astound is that I tend to use astonish and a friend of mine uses astound, but rarely do either of us use the other word. Was one of us incorrect? Is it a matter of choice? What is the difference?

From Merriam-Webster's Dictionary:

Astonish: can imply a dazing or silencing or it may mean to surprise so greatly as to seem incredible or sometimes merely unusual

Astound: stresses a stunning or overwhelming emotional effect and usually implied so great a difference between what one believes possible and what one discovers to be true that one can find no precedent for it; thus

A piece of news surprises one when it is unexpected, it astonishes when one finds it hard to believe, and it astounds when one cannot account for it by an previous knowledge or experience.

Lesson complete.