寤

Phono-semantic compound.

Semantic components:

宀 “house, roof” — sleep / indoors

爿 “bed, plank” — sleeping place

Phonetic component:

吾 (오) — gives sound (wù / 오)

Originally meant to awake from sleep, later extended metaphorically to “to understand,” “to be enlightened.”

《說文解字》 (Shuowen Jiezi ):

「寤，覺也。从宀、吾聲。」

“寤 means ‘to awaken’. Formed from 宀 with 吾 as phonetic.”

각오 (覺悟) — resolution, determination (覺 “to perceive” + 寤 “to awaken”)

오매 (寤寐) — awake/asleep; constant longing

오각 (寤覺) — awakening; realization (rare, classical)

寤 vs. 寐:

寤 — to be awake

寐 — to sleep

They often express constant longing or preoccupation:

寤寐思服 — “thinking of (someone) whether awake or asleep” (詩經).

Association with enlightenment:

Because “awakening to truth” resembles “waking from sleep,” classical Chinese often used 寤 metaphorically for “realization.”

Classical citations:

《詩經 · 邶風 · 凱風》 (Book of Songs / Classic of Poetry)

「莫之敢拒，寤寐無為。」

“None dare refuse it; In waking and sleeping, it acts without effort.”

《左傳 · 宣公十二年》 (Zuo Zhuan)

「寤而思之，寐而夢之。」

“Awake he thought of it; asleep he dreamed of it.”

Shows the pair 寤 (awake) vs. 寐 (asleep).

《荀子 · 勸學》 (Xunzi, Encouraging Learning)

「積土成山，風雨興焉；積善成德，而神明自得，聖心備焉。故不積跬步，無以至千里；不積小流，無以成江海。騏驥一躍，不能十步；駑馬十駕，功在不舍。鍥而舍之，朽木不折；鍥而不舍，金石可鏤。吾嘗跂而望矣，不如登高之博見也；吾嘗寤而思矣，不如學而不已之明也。」

"Accumulate earth to form mountains, and storms arise;

Accumulate virtue to cultivate character, and divine insight is attained, the sage's heart perfected.

Thus, without accumulating each step, one cannot reach a thousand miles;

Without gathering small streams, one cannot form rivers and seas.

A swift horse leaps but cannot cover ten paces; a plodding horse travels ten stages, its achievement in perseverance.

Carve but abandon, and rotten wood will not break; carve without ceasing, and metal and stone can be engraved.

I have stood on tiptoe to gaze afar, yet it is not as broad as the view from a height; I have awakened to ponder, yet it is not as clear as learning without end."