Examples from the Web for book bag
A book-bag or haversack, strapped around your shoulders, will also be a convenience.Our Bird Comrades|Leander S. (Leander Sylvester) Keyser
So she called Susan, and asked her to go up the street with Harry to look for his book-bag.
But he forgot that he had left his book-bag lying in the street.
Then Susan looked, and Harry looked; but the book-bag was not there.
Then his mamma asked, "How came you to put your book-bag on the step?"