The word "骷髅" (kūlóu), meaning "skeleton" or "skull", is formed by combining two characters, each structured with the semantic radical "骨" (bone) to categorize its meaning. The first character, "骷", uses "骨" for semantics and "古" (gǔ) primarily for phonetic indication, while the second character, "髅", similarly uses "骨" for semantics and "娄" (lóu) for phonetics. Together, these characters create a compound word where the shared radical reinforces the bone-related concept, and the phonetic components approximate the pronunciation.