Meaning of $64,000 QUESTION, THE in English

$64,000 QUESTION, THE

$64,000 ques·tion, the /ˌsɪkstifɔː ˌθaʊz ə nd ˌdɒlə ˈkwestʃ ə n $ -fɔːr-, -ˌdɑːlər-/ BrE AmE noun

the most important thing that people want to know about something:

The $64,000 question is whether or not the rocket will take off safely.

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.