The psychological reality of English phonaesthemes is demonstrated through a priming experiment with native speakers of American English. Phonaesthemes are well-represented sound-meaning pairings, such as English gl- , which occurs in numerous words with meanings relating to light and vision. In the experiment, phonaesthemes, despite being noncompositional in nature, displayed priming effects much like those that have been reported for compositional morphemes. These effects could not be explained as the result of semantic or phonological priming, either alone or in combination. The results support a view of the lexicon in which shared form and meaning across words is a key factor in their relatedness, and in which morphological composition is not required for internal word structure to play a role in language processing.