n.
Pronunciation: ' si-t ə -d ə l, - ˌ del
Function: noun
Etymology: Middle French citadelle, from Old Italian cittadella, diminutive of cittade city, from Medieval Latin civitat-, civitas ― more at CITY
Date: 1562
1 : a fortress that commands a city
2 : STRONGHOLD <the nation's citadel of health research ― Constance Holden> <a citadel of higher education>