Zonal is the adjective made from 'zone'. It means 'having to do with zones', or 'set out in zones'. A zone is an area that has been marked off and treated as one unit — a parking zone, a time zone, a school district. So 'zonal' describes anything organised that way: zonal pricing means the price changes depending on which zone you are in; a zonal map shows the land cut into areas; zonal rainfall means rain that falls in bands across a region.

This is a formal, technical word. You will meet it in geography books, in city planning documents, in reports about transport fares, and in science writing — not in daily conversation. If you tell a friend 'the fare is zonal', they will understand you, but they will think you sound like a government notice. Normal speech says 'it depends which zone you're in'.

One everyday place it does show up is football (soccer) and basketball: 'zonal marking' means each defender guards an area of the pitch instead of following one particular opponent. Sports commentators say it often, so if you watch English-language sports you will hear it there.

Grammar note: zonal is an adjective only. It goes in front of a noun ('a zonal system') or after 'be' ('the pricing is zonal'). There is no verb 'to zonal'.