national
The Italian word 'nazionale' is used much like its English counterpart 'national'. It is used to represent something belonging to or characteristic of a particular nation or country. It can be used in various contexts such as 'squadra nazionale' (national team), 'giorno nazionale' (national day), etc.
The national football team won the match.
This sentence refers to the national team of a country, in this case, a football team. It uses 'nazionale' as an adjective before the noun 'di calcio' to specify that the team represents a nation in football games. In the context given, they won the match.
The National Museum is one of the most visited in the country.
Here, 'nazionale' is used as part of a proper noun, 'Il Museo Nazionale', to refer to a national museum which represents a country's culture, art, etc. This sentence tells us that this National Museum is among the most visited in its respective country.
The National Library houses valuable ancient manuscripts.
In this sentence, 'nazionale' is part of the proper noun 'La Biblioteca Nazionale', referring to a national library. Such a library usually hosts a vast variety of artifacts, which symbolise the historical, cultural, and intellectual knowledge of a nation - in this case, valuable ancient manuscripts.