This Special Issue explores iconicity and sound symbolism, areas once considered peripheral to linguistics but now recognized as fundamental to language. The collection presents ten papers that advocate for viewing iconicity, not as a binary trait but as a gradient property, emerging from relationships between form and meaning. The contributions examine various dimensions of iconicity and sound symbolism, including the underlying mechanisms of iconic associations (both acoustic and articulatory), cross-modal relationships across sensory domains, cross-linguistic patterns, social and emotional dimensions, and a developmental perspective that challenges assumptions about the role of iconicity in language acquisition. Moving beyond phonemic approaches, these studies emphasize the importance of continuous acoustic and articulatory parameters in understanding iconic relationships. Collectively, they demonstrate how iconicity bridges physical and conceptual domains and is shaped by biological, cultural, and contextual factors.