It is argued in this paper that a significant number of definitions of terms provided in currently available methodological texts are inadequate or positively misleading. Some do not cover the main meaning of the term but focus instead on a non-standard one. Others fail to pick out the distinctive features of what is being defined. There are also those that fail to indicate relationships to related terms or those with similar meanings. Finally, there are some definitions that are simply incorrect in significant respects. It is argued that defective definitions are worse than useless and are a disservice to students.