The title that the ‘US economy slows in the fourth quarter’ is flatly incorrect. I checked the archive of the article and OP’s title is what the article’s title used to be. Reuter’s apparently doesn’t know the meaning of words until after they publish articles.

Fourth-quarter GDP increases at 2.3% rate

That is still growth, and a fair bit at that. The growth slowing means there is still positive growth. Saying the ‘US economy slows’ means there is negative growth, which is demonstrably not the case, as per the data in the article.

Edit: Added info about the historical title of the article and removed an incorrect statement on my part that OP mis-titled the post (Reuter’s mis-titled it, not OP).