1. a secret dungeon or underground prison with an opening only at the top, used historically to confine prisoners forgotten by the outside world
Usage: historical; often used in reference to medieval castles and fortifications
2. a place or state of being forgotten or ignored; oblivion
Usage: figurative; literary

Examples

• The castle's oubliette was discovered during renovations, revealing the grim conditions prisoners endured.
• Political prisoners were thrown into the oubliette, left to die in darkness and isolation.
• Once the scandal faded from the news, the former celebrity seemed to disappear into an oubliette of public memory.
• The old theater fell into an oubliette, forgotten by the city until recent restoration efforts began.
• Medieval fortifications often included an oubliette as a final, inescapable prison.
• His contributions to science were cast into an oubliette by later historians who credited others with his discoveries.