髓

Phono-semantic compound:

骨 (뼈 골) — semantic component, indicates bone or skeleton.

隨 (따를 수) — phonetic component, here in a shortened ancient form 遀, providing the sound sǔi / sui and implying following or connection.

In Shuowen Jiezi (說文解字):

「髓，骨中脂也。从骨，隨聲。」

“髓 means the fat within the bone; composed of 骨 and phonetic 隨.”

骨髓 (골수) — bone marrow

脊髓 (척수) — spinal cord (literally “spine-marrow”)

精髓 (정수) — the essence or quintessence of something

腦髓 (뇌수) — brain matter, the marrow of the head

神髓 (신수) — spiritual essence; the vital spirit

Shuowen Jiezi defines 髓 as “the fat within the bone,” emphasizing its material sense.

Kangxi Dictionary (康熙字典, vol. 1305):

「髓，骨中脂也。又凡物之精曰髓。」

“髓 is the fat within the bone; also, the refined essence of any thing is called 髓.”

Zhuangzi (莊子 · 知北遊):

「得其髓矣。」

“He has grasped its marrow.” — a metaphor for attaining the inner truth or essence of the Way (道).

Analects (論語 · 雍也) commentary:

“學者當求經之髓。” — “The learner should seek the marrow of the Classic,” i.e., the essential meaning rather than the surface form.

In traditional East Asian medicine, 髓 belongs to the “Five Essences (五髓)” — internal fluids that nourish the brain and spinal cord.

It came to signify the inner essence or vital core of both body and spirit.

In literature and philosophy, it represents the deepest understanding or quintessence of truth, just as the marrow is the life-giving substance within the bones.

𩪦 (U+29AA6) and 𩪷 (U+29AB7) appear in early seal and clerical scripts, but 髓 became the standard form from the Han dynasty onward.