What are y'all dilated and effaced??

🚒 laceee 🚑 • 22. Daughter born 01/27/2016.
38 weeks, 5 days today. 
Dilated to 3-4 and 65% thinned out. Doctor said I could possibly go this week but no guarantees, you never know! 
What are y'all dilated and effaced??