ˈeye-ˌopener BrE AmE noun [countable usually singular]
an experience from which you learn something surprising or new:
The whole trip has been a real eye-opener.
ˈeye-ˌopener BrE AmE noun [countable usually singular]
an experience from which you learn something surprising or new:
The whole trip has been a real eye-opener.
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012