The very first time someone reads something they never read before. With regard to technical documentation and dictionary definitions in this industry, first-time readers are even more neglected than first-time users of actual applications. The text is rarely "tested" by people actually reading the material, who have no knowledge of the concept being explained.
You Are the Expert
Unlike first-time users of software, who often feel they are not expert enough to evaluate an application, when it comes to reading a technical explanation in the English language, users are indeed experts. As a first-time reader of every definition in this encyclopedia, you are expert in evaluating what you read. If the explanation was clear, our goal was met; namely that it makes sense without having to re-read it over and over. See first-time user