There are several laws in United States and other countries regarding open carry and concealed carry. Concealed carry is to conceal a firearm to ensure it is hidden from public view, typically underneath a vest or a coat, around the leg, hip, or lower back, or at the side of the rib cage. On the other hand, open carry is carrying the gun so that it is exposed to public eye. Majority of the states permit concealed carry rather than open carry. However, few of the states have opposite view and permit individuals to carry their guns openly if they want to carry it at all.
Then there are some states where numerous in-between laws are implemented, like permitting both concealed and open carry, or requiring no permit for open carry but a permit or license for concealed carry. There is a lot of ongoing debate regarding open vs. concealed, which is quite complex what with the numbers laws in this regard, the reason no conclusion has yet been made regarding the best possible public policy.
There are still numerous issues regarding public discomfort with witnessing someone openly carrying a gun, questions of deterrent effects of concealed and open carry, technical disadvantages and advantages of both approaches during a criminal act or attack, individual rights issues, considerations about bodily comfort, and public relations worry for gun supporters.