What does it mean when the plaintiff says "we are currently in discovery" to the judge at a disposition hearin?

i just came from a diposition hearing for relief of 10,000 or less and the plaintiff attorney when it was announced said to judge"we are currently in discovery" and judge told me as I was the defendant and representing myself "to just watch your mail Ms XXX for anything important and thank-you for appearing today". I am just wondering what this means as this is the first time I have had to attend a diposition and was just quiet. Can someone give me a advice or explain legal language