Press release: a comparatively short news blurb about ongoing science. Results are typically released without being checked by other scientists in the field, or have been checked but are based only on a single study, so they are preliminary results and should be taken with a grain of salt. However, they are written in Common English, rather than Science English, and so are more comprehensible to the general public. Additionally, press releases typically come out much sooner than peer reviewed research.
I have seen my very first example of a good press release. The Boston Globe article (first part) tells how one group found that exercising pregnant mice resulted in larger brains in the offspring, but the most impressive part to the whole article is the three paragraphs after the press release, warning the reader that the results are preliminary!
The two other following blurbs do the same thing. I'm not sure when the Globe decided to do it in this manner, but I think I'm going to have to write them a letter of thanks.