ivory tower
Concise Oxford English Dictionary © 2008 Oxford University Press:
ivory tower
▶noun a state of privileged seclusion or separation from the facts and practicalities of the real world.
– origin early 20th cent.: translating Fr. tour d'ivoire, used by the 19th-cent. French writer Charles Augustin Sainte-Beuve.
'ivory tower' also found in these Oxford entries:

