The term barrier is anything meant to obstruct entrance, early 14c., barere, from Anglo-French barrere, Old French barriere "obstacle, gatekeeper," from barre "bar."
Trade barriers are government policies which place restrictions on international trade. Trade barriers can either make trade more difficult and expensive (tariff barriers) or prevent trade completely (e.g. trade embargo). Tariff barriers are taxes on certain imports raising the price of imported goods making imports less competitive. Non-tariff barriers involve rules and regulations making trade more difficult. For example, if foreign companies have to adhere to complex manufacturing laws it can be difficult to trade. Quotas are a limit placed on the number of imports. Voluntary Export Restraint (VER) are similar to quotas and is where countries agree to limit the number of imports. Subsidies from governments can give the local firm a competitive advantage. Embargoes are a complete ban on imports from a certain country.
Enter barriers, level the playing field, exit gatekeeper