What is plain/ straight text?

[thegussbus]

I have looked on the internet and in my text books, but i can't find a sensible description and example of what plain text is.
Can someone explain it to me?
I also have to identify different types of media and discuss there advantages compared to straight text?

 

[SkyNetRising]

You can google it:
define: plain text

https://en.wikipedia.org/wiki/Plain_text