壹

Phono-semantic compound:

壺 (호, “jar, vessel”) — semantic, originally indicating something enclosed or contained.

吉 (길, “auspicious, good fortune”) — phonetic, providing the sound 일 and connoting completeness or correctness.

Originally, the character depicted 吉 enclosed within 壺, symbolizing something unified and contained — hence the meaning “one,” “whole,” or “complete.”

일심(一心) / 일심(壹心) — one heart, wholehearted devotion

일체(一切) / 일체(壹切) — all, entirety

일원(一員) / 일원(壹員) — one member (formal writing)

일금(壹金) — one amount of money (used in contracts or receipts)

壹 is mainly used in official documents, certificates, and contracts to prevent tampering or misreading, where 一 might easily be altered into 二 (“two”) or 三 (“three”).

In classical Chinese philosophy and Confucian texts, 壹 carries the extended moral sense of single-mindedness, integrity, and unity of purpose.

《孟子·告子下》:

「君子之於道也，無所不用其極，壹以貫之。」

“The gentleman applies himself to the Way with utmost effort — united and consistent throughout.”

Here, 壹以貫之 means “to unify one’s principles and carry them through consistently.”

《禮記·中庸》:

「誠者，非自成而已也，必也崇德而壹。」

“Sincerity is not self-sufficient — one must exalt virtue and make it one (壹).”

壹 denotes inner concentration and moral unity.

In such passages, 壹心 (일심) and 壹志 (일지, “one intention”) express the Confucian ideal of focused virtue and undivided loyalty.

壹 thus embodies both numerical unity and spiritual integrity, bridging practical and philosophical meanings.