midway, as between two places or points. going to or covering only half or part of the full extent: halfway measures.

Is half way or halfway?

Both are acceptable but halfway is more common, as in: Meet me halfway on this. Or, He lives at the halfway house. Jim stopped part way across the bridge. He thought he'd made the halfway point.

Does halfway need a hyphen?

The noun way constitutes the second half of many compound words. Almost all of them, like halfway, are closed, but a couple retain a hyphen or are open.