What is a polyfuranoside?
The term polyfuranoside is a combination of 


the Greek prefix poly, which means many and
the term furanoside, which indicates that the structure is somewhat related to furan, a five-membered (aromatic) heterocycle that contains an oxygen atom. Forget about the aromaticity here, what counts is


five-membered ring
contains an oxygen atom



If you take a look at the large diagonal of the structure, you'll recognize a large number (12) of these structure elements connected by glycosidic bonds, hence the other description, docosanasaccharide.