ABD is All But Dissertation. It is generally used to indicate people who have completed all the requirements for a Ph.D. except for the dissertation. The completed requirements usually include coursework, qualifying exams and other preparatory work. It may also include having completed a teaching requirement, data collection, certifications, even writing the dissertation, but not having defended or completed rework yet.
This is not an official degree, but is a recognized term by graduate students in many fields.