What Does Flattening the Curve of COVID-19 Mean?

It is pretty basic. You can take the peak of infections out of a pandemic by implementing social distancing early in the event. See the diagram below. 

The challenge for us here in the United States is we don't know where we are on the timeline of the X axis below. Without the test kits, we are driving blind and guessing where we are on the road of the pandemic. 

Is social distancing being implemented "just in time" or did we miss our opportunity to take action? Are the actions being taken significant enough to "flatten the curve?" Only time will tell.