Lost sheep
One sheep separated from the flock — the single member that has wandered out of the safe field.
A lost sheep in a dream is the dream's image of the single member that has wandered out of the safe field. The flock keeps moving; the lost sheep is heard from a long way off and is the one the shepherd has to leave the ninety-nine for. The dream brings the lost sheep when something in your life — a family member at the edge of the family, a friend losing contact, a piece of yourself that has drifted from the rest — is currently the one figure that the larger group cannot proceed without recovering. A lost sheep found and carried back is the dream affirming that the recovery is possible. A lost sheep heard fainter and fainter, with the flock moving on without pause, is the dream noting that the stray is being allowed to keep drifting, and the field the rest stay in is going to be smaller by one.