A Hymn ,as far as I am concerned, means the national song of a country that prises the country and its principles. A hymn represents the country in political issues i.e: when there is a world conference or a summit to discuss serious issues. It also represents the country in sports events such as the olympic games or world cup. And according to a google search, wikipedia:
"A hymn is a type of song, usually religious, specifically written for the purpose of praise, adoration or prayer, and typical