In this study, I examined preschool storybook apps for the affordances they may provide for young children's vocabulary development. Specifically, I sought to understand (a) the degree to which storybook apps introduce new words, (b) the types of words children can learn, and (c) the degree to which digital enhancements align with new words in the story. To do so, I conducted a content analysis of 26,744 words in 70 best-selling storybook apps in the United States. Results indicate that approximately 7.5% of words in preschool storybook apps might be considered new words for preschool children--which is comparable to the number of new words in preschool printed books. Furthermore, approximately 25% of new words in storybook apps are aligned with digital enhancements. These findings contribute new information about vocabulary in preschool storybook apps and the extent to which digital enhancements might support children's word learning on screen.