The word 松子 is formed by directly combining two characters: 松 (sōng), meaning "pine tree", and 子 (zǐ), a common suffix meaning "seed" or "small object". It is a straightforward, literal compound where the first character specifies the source (the pine tree) and the second character specifies the object produced (the seed), together creating the meaning "pine nut". The formation is purely semantic, picturing the seed that comes from a pine cone.