The number of contracts still alive at the end of a session. It rises when a new holder and a new writer create a contract between them and falls when both sides close; a position simply changing hands does not move it. Read together with the change in price it gives the four-state classification this desk prints per strike.
Mayawhat these words mean
Maya reads the desk’s written explainers and the glossary. She holds no market data at all, so she can say what a thing is and cannot say what it is doing today.