Every academic field has its share of confusing technical terms. Their redeeming feature is that they lend precision to scholarly discussion, but in some cases, a word may have different meanings in different contexts. For example, the word abduction has specific definitions in the legal realm (a kidnapping); formal logic (a syllogism with a major premise that is certain and a minor premise that is merely probable); and anatomy (the action of moving a part of the body away from the midline). Technical terms also bedevil meteoritics; some terms don’t have exactly the same meaning as in common parlance. In some cases, the following definitions differ from those approved by the International Astronomical Union (IAU), but the set presented here is precise and self-consistent. We recommend its adoption by astronomers, geologists, cosmochemists, and planetary scientists. Terms are arranged topically, not alphabetically.