What is the comparative and superlative form for word wide?

The word "wide" is already an adjective, so you don't need to change it to form comparative and superlative forms. Here's how you would use "wide" in those contexts:

* Comparative: "wider" (e.g., "This road is wider than the other one.")

* Superlative: "widest" (e.g., "This is the widest river in the world.")