Collectible Card Game Headquarters

I'm sorry for asking this but as English isn't my mothertonge, I don't understand this concept well.

What is Milling (Milling=loss condition)? Does it mean that if you (or compy) don't have more cards in your deck, you lose the match?

Thank you for the future answers.

Yes, basically without this option checked players don't lose if they try to draw from an empty library.

"Milling" is a wide-spread term used in this manner, due to one of the first cards to use the effect, Millstone .

Ok, thank you both.