孙子
sūnzi · HSK 4
grandson
👦 孙子 = grandson + child (孙 grandchild + 子 child/son)
孙 means descendant/grandchild and 子 means child or son, so 孙子 literally stacks the two to mean a son's son. Same 子 you see in 儿子 (son) and 女子 (female).
子 — pictograph of a baby/child with arms out
子 began as a pictograph of a swaddled infant with a large head and outstretched arms, originally meaning 'baby' or 'child.' From there it broadened to 'son,' 'offspring,' and a respectful suffix for masters like 孔子 (Confucius). It also became one of the twelve earthly branches.