Don Valentine from Sequoia Capital might have coined the term. While Marc Andreessen from A16z popularised it as “being in a good market with a product that can satisfy that market.”
According to Andreessen, that is when a product or service has its place in the market, thus enabling traction for the company offering that product or service.
In an interview with Mike Maples, Andy Rachleff, who cofounded the firm Benchmark Capital and is a co-founder and CEO of Wealthfront, explains the term's origin.