| 释义 |
| | | | NOUN | | | | | /ˈsɪtədl/ | | | | /ˈsɪtəˌdel/ | | | | | 1 | a castle intended originally for the defence of a city , usually built on a high place （护城）城堡 | | | | 2 | +of: literary a place that seems to represent all the important aspects of an idea , method , or practice （代表思想、方法、习俗等的）中心，堡垒 | a citadel of learning 知识的堡垒 | | | |