Why is it "on holiday" in the first sentence, but "on a holiday" in the second sentence?

In December 2019, Teo posted a picture of himself while on holiday in Japan. The boy was also on a holiday in Japan and added Teo on Instagram.

Why is it “on holiday” in the first sentence, but “on a holiday” in the second sentence?


This is a British and European use of the term vs American use.

In the US, “a holiday” usually means the day itself. For example Christmas is a holiday.

In Europe, “holiday” refers to what Americans usually call a vacation. It refers to the time period and travel, not the day.

With either word, not using the article is more common in Europe, whereas in the US, it’s more common to use the article.