The word 橡胶 (xiàngjiāo, meaning "rubber") is formed through a direct and descriptive combination of two characters: 橡 refers to the "oak" tree, but historically in Chinese it extended to rubber-producing trees like the rubber tree, representing the plant source; and 胶 means "glue" or "adhesive", representing the sticky, elastic substance produced. Thus, the compound literally and conceptually blends the source (the tree) with the key property of its product (the glue-like material) to create the meaning for the resilient, flexible substance we call rubber.