古

Composed of 十 (열 십, “ten”) + 口 (입 구, “mouth”), and is traditionally regarded as an ideogrammic compound.

The 口 is often interpreted as “speech” or “words,” while the 十 has two main interpretations:

• “Very large number” theory – 十 is taken to mean “a great number,” symbolizing stories and traditions passed down orally over countless generations, leading to the meaning “ancient times.”

• “Shield/armor” theory – 十 is seen as a variant of 干 (shield) or 甲 (armor), suggesting that stories about old battles gave rise to the meaning of “old” or “ancient.”

In oracle bone script (甲骨文 jiǎgǔwén), the form of 十 varied:

• sometimes drawn as a stick piercing through 口,

• other times drawn without piercing it.

This has led to different interpretations of its original image — some think it even looks like a church symbol on a map or a tombstone with a stele in front of it.

故 a similar in meaning:

古 = “old, ancient” - comparable to past tense in English: describing something from long ago.

故 = “reason, tradition, something continuing from the past” - comparable to present perfect tense: something from the past that still has effect now.

Despite these nuances, 古 and 故 are sometimes interchangeably used in historical and literary contexts.