"Depth of View" as seen through a microscope?

I feel your pain. I don't think any biology teacher actually tells you what it is, they just expect you to know it. It's the focus of the microscope. For example that thread thing, if you have a red, green, and blue thread, then when you see the red thread clearly, then you twist the knobs and see the blue thread clearly, your changing the depth of focus. It's basically what level your looking at clearly. Level meaning like levels of a building, like floors. I'm sorry if u didn't get that. Good luck