Definition of national product in English:
national product
noun ˌnaʃ(ə)n(ə)l ˈprɒdʌktˌnaʃən(ə)l ˈprɒdʌkt
The monetary value of all goods and services produced in a country in a given period (usually one year).
Origin
Late 19th century; earliest use found in Science. From national + product.