But toward the end of the definitions you'll also see “-wide” with a little hyphen on front. The dictionary calls this a “combining form,” meaning you combine it with another word. ... So when you're writing "storewide," you're not combining two words or a word and a suffix. You're using a single word.

Is storewide one word?

store•wide

adj. applying to all the merchandise or departments within a store: a storewide clearance sale.

What is a storewide?

: including all or most merchandise in a store a storewide sale.