Evolutionary Development
This is when the actual development happens. We divide the project into increments (typically 4-6 weeks), deciding at the end of the previous increment which requirements we'll focus on in the next increment. It's further sub-divided into 2 week timeboxes, keeping the development tightly focused. It includes regular testing during each increment, to catch bugs and other issues early, when they're easier to change.
Evolutionary Development is cyclical with Deployment, as the project moves back and forth between stages.