Zincs largest use is in corrosion protection. Galvanising is the main method of protection against corrosion of steel, i.e. the steel is coated with a layer of zinc in order to protect it from decay.
Zinc (Zn) has some health benefits. Aside from being a nutritional supplement it is also used for metal coating and rust protection. It is one of the primary components of pennies. You can find more information here: http://www.chemicalelements.com/elements/zn.html
Zinc is used for many things. Some of these include paint, dyes, cough drops, X-rays, rubber, batteries, coins, car parts, and televisions.