While I imagine it is an act of terrorism, I can see the reluctance to label it as such. A really important defining characteristic of terrorism is that it’s used to promote a cause, and those responsible come forward fairly quickly. As this hasn’t happened yet, the tragedy in Boston may not fall within the traditional parameters of terrorism. However, it’s historically been a very difficult term to define. Whatever you call it, it’s a horrific tragedy, and my best wishes go out to all those affected, and to the beautiful city of Boston, which I had the pleasure of visiting in October.