[zminjie]

It is defined in the linked blog post and I believe it's a pretty good definition.

“The customers are buying the product just as fast as you can make it — or usage is growing just as fast as you can add more servers. Money from customers is piling up in your company checking account. You’re hiring sales and customer support staff as fast as you can.”

[mwseibel]

I’m pretty sure Marc invented the phrase so he gets to define it: https://pmarchive.com/guide_to_startups_part4.html

[ttul]

In other words: your growth is so astonishing that it justifies paying >30% IRR to investors rather than growing from internal cash or borrowing what you can from a bank.

[mbesto]

> It is defined

There's not an agreement on a single definition though - that's my point https://www.quora.com/How-do-you-define-Product-Market-Fit