What does the word an mean?

Usage examples for an

  1. It would be such an easy way out. – 32 Caliber by Donald McGibeny
  2. The little, old woman seemed like an old friend to her. – Four Girls and a Compact by Annie Hamilton Donnell
  3. Why is it an answer to say we must do that to make them Distributists? – Gilbert Keith Chesterton by Maisie Ward