The word 扩散 is formed by combining two characters, each contributing a core action to the concept: 扩 (kuò), meaning "to enlarge" or "to expand", conveys an outward pushing or broadening, while 散 (sàn), meaning "to scatter", "to disperse", or "to disseminate", conveys a movement away from a central point. Together, they create a compound where the action of 扩 modifies and intensifies the action of 散, pictorially and conceptually representing the process of something (like gas, information, or an effect) expanding its boundaries while simultaneously scattering its components outward.