Interestingly, their nickname derives from Yamato Nadeshiko a Japanese term meaning "personification of an idealized Japanese woman". Virtues include loyalty, domestic ability, wisdom and humility. It's a floral metaphor combining Yamato, an ancient name for Japan and Nadeshiko, a frilled pink carnation. (More here.) Personally I think the Japanese team has just modernized the definition. Before yesterday, the nadeshiko referred to Japanese women with "good old" traits, today I think it means you can have good old traits and still be modern, strong, fierce, driven, and athletic - not your traditional domestic goddess but a goddess nonetheless!
The US fell to a team to whom the victory meant so much more than just a title. And no one could have said it better than Carli Lloyd - "If any other country was to win this, then I’m really happy and proud for Japan. Deep down inside I really thought it was our destiny to win it. But maybe it was Japan’s.”