Music or sound professionals use specific terminology to communicate about timbre. Some key terms do not come from the sound domain and do not have a clear definition due to their metaphorical nature. This work aims to reveal shared meanings of four well-used timbre attributes: bright, warm, round, and rough. We conducted two complementary studies with French sound and music experts (e.g., composers, sound engineers, sound designers, musicians, etc.). First, we led interviews to gather definitions and instrumental sound examples for the four attributes (N = 32). Second, using an online survey, we tested the relevance and consensus on multiple descriptions most frequently evoked during the interviews (N = 51). The analysis of the rich corpus of verbalizations from the interviews yielded the main description strategies used by the experts, namely acoustic, metaphorical, and source-related. We also derived definitions for the attributes based on significantly relevant and consensual descriptions according to the survey results. Importantly, the definitions rely heavily on metaphorical descriptions. In sum, this study presents an overview of the shared meaning and perception of four metaphorical timbre attributes in the French language.