1) Be central or dominant 2) Dominate 3) Form an arch over 4) Loom large 5) Predominate 6) Prevail 7) Reign 8) Rule 1) Span 
• (v. t. & i.) To make or place an arch over; to hang over like an arch.
O`ver·arch' transitive verb & i. To make or place an arch over; to hang over like an arch. 'Brown with o'erarching shades.' Pope. 
[v] - be central or dominant 2. [v] - form an arch over
to span with or like an arch: A new bridge overarches the river.