What does the saying dodged a bullet mean?

If you dodged a bullet, you had a very narrow escape. The image is of someone actually managing to get out of the way of a bullet fired at them. If you barely escaped something bad, you'd say "I really dodged the bullet." This is usually a figurative danger rather than a literal one -- mostly you hear the phrase in terms of a bad situation at work or home. An example would be "You really dodged the bullet when you managed to convince the boss that you really were home sick yesterday."