Have you ever heard anyone refer to wedges as "fries?"
Have you ever seen a restaurant menu use the terms "fries" and "wedges" interchangeably?
Have you ever seen packaged fries labeled as "wedges", or packaged wedges labeled as "fries?"
Have you ever been served wedges under the guise of being served "fries?"
A sandwich is something (usually a meat or other savory substance) which is placed (sandwiched as it were) between two other things (bread or some other starchy foodstuff). Such an item would be called a something sandwich.
Is it a bread sandwich, or 3 slices of bread?