Produced domestically; made in the country (as opposed to imported or foreign-made).
この車は国産で、部品の多くも国内製だ。
This car is domestically made, and many of its parts are also produced in the country.
国産の野菜を買うようにしている。
I try to buy domestically produced vegetables.
最近は国産ビールが人気だ。
Domestic beers have been popular recently.