What is Balance Of Trade?

Legal Definition
The commercial balance or net exports (sometimes symbolized as NX), is the difference between the monetary value of a nation's exports and imports over a certain period.

If a country exports a greater value than it imports, it is called a trade surplus, positive balance, or a "favourable balance", and conversely, if a country imports a greater value than it exports, it is called a trade deficit, negative balance, "unfavorable balance", or, informally, a "trade gap".

Sometimes a distinction is made between a balance of trade for goods versus one for services. Generally trade surplus is seen as positive economic indicator however in exceptional circumstances trade deficit is due to government forex policy to achieve other macroeconomic goals.
-- Wikipedia
Legal Definition
The biggest element for a country in their balance of payments accounts. The difference between export and import is shown. More export is good. AKA trade balance.
Legal Definition
Com. law. The difference between the exports and importations, between two countries. The balance of trade is against that country which has imported more than it has exported, for which it is debtor to the other country.
-- Bouviers Law Dictionary