fur-
combining form 
or furo-
Etymology: International Scientific Vocabulary, from furfural 
1. : related to furan 
< furodiazole >
furfural
< furoin >
or furoic acid
< 2-furamide >
2. : containing a furan ring fused on one side to one side of another ring 
< furoquinoline >
or furo-
1.
< furodiazole >
furfural
< furoin >
or furoic acid
< 2-furamide >
2.
< furoquinoline >