What is this “momentum” of which you speak?

A meeting with an entrepreneur last Friday reminded me of the most frustrating and overused feedback entrepreneurs receive from VCs:
Talk to me when you have “momentum”; or

I need to see some “traction” first.
With more and more VCs looking to make later stage investments, entrepreneurs are receiving this feedback more than ever. You can understand why an entrepreneur might find this feedback frustrating. If they had massive traction, they probably wouldn’t need VC money, or if they did, the deal should be priced at a much higher valuation. That said, the real issue with this feedback is that it triggers a conversation about the definition of momentum. Entrepreneurs complain (rightly so I might add) that the VC definition of momentum comes in the following forms: 1) VC defines momentum by saying; “I know it when I…

What is this “momentum” of which you speak?