So I was writing my post about fault and responsibility and needed a page about responsibility. And this is it, but I’m going to put something useful later, not now.
And I’ll add a little more right now, the next day or so:
According to Google responsibility is the state or fact of having a duty to deal with something or of having control over someone.
And Merrian-Webster says something like the quality or state of being responsible as moral, legal, or mental accountability. And mentions something like reliability and trustworthiness.
And Wikipedia makes it a bit more interesting by mentioning all kinds of responsibility: responsibility on Wikipedia.