The "European Championship" is a major football tournament held every four years, showcasing the best national teams from Europe. In English, it is commonly referred to as the "UEFA European Championship" or simply the "European Championship." Here's how you write it:
1.
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In both cases, "European" is capitalized because it's part of the proper noun referring to the championship. "Championship" is also capitalized as it's part of the title.
When writing about the tournament, be consistent with your choice of terminology. If you're writing formally or referring to the governing body, you might use "UEFA European Championship." In casual conversation or writing, "European Championship" works just fine.