單

Phono-semantic compound, with debated origins.

Graph shows 甲 (armor / shell) + 口 (mouth) arranged under a roof (宀-like).

Interpreted as “a single piece” or “unit,” hence “single, one.”

Later borrowed (假借) for tribal names and place names.

單一 (단일) — single, unitary

簡單 (간단) — simple, easy

單獨 (단독) — alone, independent

單車 (단차) — bicycle (lit. “single vehicle”)

單位 (단위) — unit (measure, organization)

單于 (선우) — title of the Xiongnu ruler, “Chanyu”

In Chinese history, 單 (선) appears in 單于 (Chányú, 선우), the supreme title of Xiongnu rulers, comparable to “khan” or “emperor.”

In Korean usage, 單 most often means “single, simple” (단일, 간단).

In classical texts, distinction between 單 (단) and 單 (선, tribal/onomastic use) was maintained by context.