The word 一言九鼎 is formed by the direct combination of 一 (one), 言 (word), 九 (nine), and 鼎 (ancient ceremonial cauldron), literally meaning "one word, nine dings". It originates from a historical event where nine dings represented imperial authority, so the phrase uses this tangible comparison to convey that a single statement is as weighty and trustworthy as these sacred vessels, thus forming an idiom meaning one's words are of great consequence.