In some cases, most people don't even know what the letters actually stand for.

No, she does not know what the letters stand for.

If the letters stand for anything, no one knows what.

I got out of the car and asked the driver what the letters stood for.

In addition to sounds, each letter stands for several common short words.

Each letter stands for a condition that needs to be considered.

What the letters stand for in this game is not specified.

He couldn't remember what the letters stood for but it was poison.

The letters do not always stand for the same sounds as in Greek.

I had to ask someone what those letters stood for.