What exactly counts as a publication

[Virago]

Does an article published in a newspaper (part of an internship where I visited museums and wrote press releases and exhibition reviews) count as a publication?

[Quant_Liz_Lemon]

Not as a peer reviewed article.

[fullofpink]

If you hold a BA and the exhibition review was actually a review of the exhibition (as opposed to simply a description of the exhibition, similar to a press release), then yes. You can include it. If you already hold a MA, you should be concentrating on academic publishing. Unfortunately, the press releases do not count. 

[Quantum Buckyball]

Does an article published in a newspaper (part of an internship where I visited museums and wrote press releases and exhibition reviews) count as a publication?

A review paper should be considered as a publication.

However, you should indicate that it was a review paper instead of a peer-reviewed research journal paper.

[Bearcat1]

Since it's rare for art historians to have published much before the PhD candidacy stage, I think you should absolutely include it on your CV/apps. Of course, be explicit about what it is and there won't be any confusion.