P vs NP
/piː vɜːrsəs ɛn piː/ · Noun · Development · Origin: 1971
Definitions
The most important open question in computer science: whether every problem whose solution can be verified quickly (NP) can also be solved quickly (P). A Clay Millennium Prize Problem worth $1 million.
In plain English: Can every problem that's easy to check also be easy to solve? Nobody knows, and it's the biggest unsolved puzzle in computing.
Example: "If you could prove P = NP, you'd break most of modern cryptography — and win a million dollars doing it."