As the title says... Like you can in ArcMap?
FAQ: Is it possible to control the zoom extent of an ArcGIS Online web map?
scale - Limit Zoom Levels in ArcGIS Online WebMap - Geographic Information Systems Stack Exchange
You can also vote here:
ArcGIS Online - Need to prevent users from zooming in too close or out too far
Thanks Ricky. That works just as well!
Retrieving data ...