唯

Formed as a compound character:

口 (mouth, speech) represents speaking or vocal expression.

隹 (short-tailed bird) provides the phonetic element and originally implied a chirping sound.

In early oracle bone forms, 唯 often appeared simply as 隹, used as a copula (“to be,” like modern 是). Over time, the addition of 口 emphasized its function in spoken affirmation.

Semantic range:

- only, solely (오직, 유일);

- yes, to affirm, to assent (특히 아랫사람이 윗사람에게 긍정하는 말);

- formerly used as a copula “to be” (replaced by 是 in modern usage).

유일 (唯一) — only, unique

유독 (唯獨) — only, solely

유가 (唯我) — only I, self alone

유심론 (唯心論) — idealism (lit. “only-mind theory”)

유물론 (唯物論) — materialism (lit. “only-matter theory”)

In Chinese philosophy, 唯 gained particular significance in Buddhist and later Neo-Confucian discourse. The compound 唯心 (“only mind”) lies at the core of Buddhist Yogācāra thought, asserting that reality is fundamentally shaped by consciousness.

Similarly, 唯 appears in major philosophical dichotomies such as 唯物論 vs. 唯心論, framing debates about the primacy of matter or mind. Thus, while seemingly simple (“only”), the character has shaped deep metaphysical discussions across East Asian intellectual history.