In this article we report on listener categorization of meaningful environmental sounds. A starting point for this study was the phenomenological taxonomy proposed by Gaver (1993b). In the first experimental study, 15 participants classified 60 environmental sounds and indicated the properties shared by the sounds in each class. In a second experimental study, 30 participants classified and described 56 sounds exclusively made by solid objects. The participants were required to concentrate on the actions causing the sounds independent of the sound source. The classifications were analyzed with a specific hierarchical cluster technique that accounted for possible cross-classifications, and the verbalizations were submitted to statistical lexical analyses. The results of the first study highlighted 4 main categories of sounds: solids, liquids, gases, and machines. The results of the second study indicated a distinction between discrete interactions (e.g., impacts) and continuous interactions (e.g., tearing) and suggested that actions and objects were not independent organizational principles. We propose a general structure of environmental sound categorization based on the sounds' temporal patterning, which has practical implications for the automatic classification of environmental sounds. (Contains 8 figures, 7 tables, and 5 footnotes.)