Applying several names to an entity (polynomy) reflects the ability to categorize entities in different ways. Two experiments demonstrate preschoolers' abilities to apply multiple labels to representational objects and to people. In Experiment 1, 3- and 4-year-olds labeled representational objects and verified labels for story characters. In both tasks children reliably produced or accepted several words per entity and accepted a high percentage of both class-inclusive and overlapping word pairs. These results were replicated in Experiment 2; 3- to 5-year-olds also completed appearance-reality and receptive vocabulary tests. The mean number of words produced in the labeling task was significantly related to receptive vocabulary, but not to appearance-reality performance. The results indicate that preschoolers represent an entity as belonging to multiple categories (e.g., dinosaur and crayon). Implications for cognitive and language development, particularly the appearance-reality distinction and the mutual exclusivity bias, are discussed.