We have a great community wiki that defines many of the terms used in lenses here: What do all those cryptic number and letter codes in a lens name mean?
I recently asked the question: What is USM, and what are its pros and cons? I asked it not because I didn't know what the acronym stood for, but because I wanted to understand the details, reasons why you would want it, types of it, pros/cons, etc.
The issue I am wondering about is if we have this great community wiki with definitions for lens terminology, is it OK to ask further questions to get the details, or do we want to turn the community wiki that is already very long into an even longer answer?
My next example is the terminology DO, yes it defines it as Diffractive Optics in the wiki, but I have no idea what that means, and I don't see another question that asks all of the details of it.