inner sanctum
noun
1- the most sacred place in a temple or church寺庙禁地; 教堂禁地。
1.1
- figurative a private or secret place to which few other people are admitted〈喻〉（很少允许外人进入的）私人禁地; 秘密处所：
he walked into the inner sanctum of the editor's office.
他走进了编辑室的禁地。