rule of the shorter term

noun1

1. •
   A feature of the copyright law of some countries, whereby the duration of protection granted by the country in question to a work created in a foreign country is limited to no greater than that which it would have received in its country of origin, even if it would have been eligible for a greater duration had it been created in the country in question; the rule that, when a copyrighted work passes into the public domain in its country of origin, it will also pass into the public domain in the country in question if it has not already done so.