A tax on goods that are brought into the country and compete with that country's own products. It is designed to drive up the cost of foreign goods and protect native manufacturers from disruptive competition.
A protective tariff is a tariff or tax imposed on goods imported from other countries in an effort to "protect" goods made within the country. It makes foreign goods more expensive than local goods and hopefully less appealing to buy. As a result, the protective tariff helped American industries financially by luring the people with lower prices.