General cognitive ability is still a factor in current definitions of dyslexia despite two decades of research showing little or no relevance to the nature of dyslexia. This article suggests one reason why this may be so. The suggestion is based on a distinction between dyslexia as a disability (poor ability)--as it is viewed and explained by psycholinguistic and neuropsychological research--and dyslexia seen as a handicap (the consequences of a poor ability) in the educational world. While general knowledge and ability may be irrelevant to the nature of dyslexia as a disability, general knowledge and ability does relate to an ensuing handicap. Vocabulary is possibly the most closely linked subcomponent of "general knowledge and ability" to reading. It was thus hypothesized that when reading ability was controlled individuals with high vocabulary would be more likely than others would to experience a reading handicap as a function of poor reading. Conversely, vocabulary would not relate to the severity of the reading disability per se. These hypotheses were supported by results from a study of 165 adult poor readers. (Contains 2 figures and 3 tables.)