The Chinese word **添加** (tiānjiā), meaning "to add," is formed through a common process in Mandarin known as **synonym compounding**, where two characters with similar meanings are combined to create a single, more precise or emphatic term. The character **添** (tiān) itself carries the meaning of "to increase" or "to add to," while **加** (jiā) means "to add," "to plus," or "to include." By joining these two synonymous morphemes, the compound word **添加** reinforces and nuances the core concept of addition, often implying a deliberate or supplemental action, and results in a standard modern verb that is stronger and more specific than either character used alone.