A native speaker of Japanese has asked if ゴールデンウィーク is wasei eigo.
The Wikipedia article on Golden Week in Japan claims that the term was created in 1951.
However, a google ngram search for English indicates that the combination "golden week" (and possibly "Golden Week") gets some hits before 1951.
I was also confused by the fact that China also has a Golden Week, but that seems to have been created fairly recently.
Is the term ゴールデンウィーク wasei eigo?