锦囊 literally means 'silk bag' — a small ornate pouch used in ancient China to hold valuables or documents. But the word is most familiar from the idiom 锦囊妙计 (jǐn náng miào jì, 'wise advice in a silk bag'), based on the Romance of the Three Kingdoms story where Zhuge Liang gave Zhao Yun sealed bags with strategies to open at critical moments. Today, 锦囊 can also be used metaphorically for 'a ready solution' or 'a clever plan', especially in 锦囊妙计 as a set phrase. The literal use is rare in modern conversation; you'll mostly encounter it in historical or figurative contexts.