膠

Originally referring to animal glue made from boiled hides and bones, 膠 later came to mean any adhesive material or act of sticking, and by metaphor, close attachment or inseparability between people or things.

Phono-semantic compound consisting of:

肉 (⺼, 고기 육) — semantic component, indicating relation to flesh or material derived from animals.

翏 (높이날 료) — phonetic component, giving the sound jiāo / gyo, also implying lightness, flexibility, or spreading motion.

Shuowen Jiezi (說文解字):

「膠，牛馬皮角之所煑也。从肉，翏聲。」

“膠 is what is boiled from the skins and horns of cattle and horses. Composed of 肉 (‘flesh’) and the sound 翏.”

Thus, 膠 originally denoted the gelatinous substance extracted by boiling animal parts, used for binding, gluing, and even medicinal tonics.

Its phonetic part 翏 (also written in ancient texts as 僚 / 燎 interchangeably) supplied the pronunciation gyo and a secondary image of melting and spreading, aligning with glue’s nature.

阿膠 (아교) — animal glue; gelatin (traditional medicinal substance)

魚膠 (어교) — isinglass; fish glue

膠水 (교수) — glue or adhesive liquid

膠合 (교합) — to glue together; to bind or join

膠着 (교착) — adhesion; fixation; stalemate (lit. “stuck together”)

膠片 (교편) — film material (lit. “glue sheet”)

膠囊 (교낭) — capsule (pharmaceutical sense)

膠漆 (교칠) — glue and lacquer; to bond strongly

In ancient China, 膠 (animal glue) was a crucial craft material:

Used in bookbinding, lacquerwork, instruments, bows, and furniture;

Valued in medicine, especially as 阿膠 (donkey-hide gelatin) — prescribed to nourish blood and restore vitality;

Symbolically linked with adhesion, fidelity, and steadfastness.

The phrase 膠漆之交 (교칠지교) — “a friendship like glue and lacquer” — signified an inseparable, loyal bond.

「膠漆之交，不可離也。」 (Han Shu)

“Their friendship, like glue and lacquer, cannot be parted.”

Thus, from a physical adhesive, the word took on moral and emotional meanings — steadfast attachment, devotion, or fixation.

Cultural and symbolic meaning:

膠 transcends its material sense to embody several layers of meaning:

Material — glue, adhesive substance derived from animal matter.

Craftsmanship — the unseen binding force in art, literature, and creation.

Moral / emotional — unwavering loyalty, attachment, or bond (膠漆之交).

Philosophical — the tendency of the mind to cling, to become stuck or attached, especially in Buddhist discourse.

In Daoist writings, excessive “adhesion” (膠著) represents the obstacle of fixity — the inability to flow with the Dao.

「膠者滯也，滯則不通。」

“That which sticks is stagnant; stagnation blocks the Way.”

In Buddhist texts, 膠 often symbolized attachment and entanglement, as in:

「情膠於世，難以自脫。」

“Affections stick to the world like glue — difficult to free oneself.”

Across Chinese, Korean, and Japanese traditions, 膠 endures as a symbol of unity, loyalty, and the subtle bond that holds things — and people — together.