The current paper investigates two productive morphological processes, namely compounds and portmanteau words (or blends). While compounds, a productive, regular and predicable morphological process, have received much attention in the literature, little attention was paid to portmanteau words, a creative, irregular and unpredictable word formation process. The present paper aims to find the commonalities and differences between these morphological devices, using Rosch et al.’s (1975; 1976) theory of prototypes and basic-level categories to achieve this goal. This theory will also be (...) employed to discuss the literature on the word formation mechanisms under investigation and propose a new categorization approach to these neologisms. The analysis suggests that compounds and blends compare and contrast and that the distinctions between them are blurry. The analysis confirms that a prototypical approach is well suited to compounds and blends in English. This has implications for future research into English word-formation processes in general and compounds and blends precisely. (shrink)