|00:53Bow is a banjo neck condition caused by long term string pressure curving the neck so that the neck curves upward as you approach the nut. Most old banjos have some bow in the neck. Slight bow can be corrected by placing a thin wooden shim between the neck and the pot at the top of the pot. More severe bowing can sometimes be corrected by a professional using heat to soften the glue under the fingerboard and pressure to force the neck back to shape.
Instruments with truss rods can often correct this problem by adjusting the truss rod. Though this is simple, unless you know what you are doing it should be left to a competent luthier. Proper use of a truss rod involves seasonal adjustment to account for dry air in the winter that allows bowing of the neck and moist air in the summer that causes a warping action. Typically the rod is tightened in the winter and loosened in the summer.