A government imposed restriction on the free international exchange of goods or services.
Trade barriers are generally classified as
1.import policies reflected in tariffs and other import charges, quotas, import licensing, customs practices
2.standards, testing, labeling, and various types of certification,
3.direct procurement by government,
4.subsidies for local exporters,
5.lack of copyright protection,
6.restrictions on franchising, licensing, technology transfer,
7.restrictions on foreign direct investment, etc.