be on the way (to someone or some place)

1. To be currently en route to someone or some place. We're on the way to the party now. We should be there in five minutes. A: "Dad, can you come pick me up from soccer practice?" B: "Sure thing, pal. I'm on the way!" Please tell me you're the your way. I'm giving them the slowest service in the history of waitressing, but I can't keep them here forever!

2. To be found or located along the route to someone or some place. I know of a good florist that's on the way to your parents' house. We should pick up some flowers for them before we get there. A: "You're sure you don't mind driving me to school?" B: "Not at all. It's on the way." The store is on the way home, so let's just pick up some milk when we're coming back.