Tidings are information or news. However, there are a few critical differences. Well, in practice anyway.
1. "Tidings" seem to carry an air of an earlier time, perhaps with an almost medieval or Shakespearean feel to it. Probably doesn't hurt that it appears 41 times in the King James Bible. Of course, feel is a relative thing, so I suppose this is largely dependent on who you ask.
2. Because of this, you can use more easily get away with such phrases as "I bring you glad tidings". In fact, feel free to add "m'lord" at the end.
3. You can have a tiding. That's right. You can also use the singular "tiding" if you only have a single piece of news. Or would that be a single piece of new?