Why does timeOut turn orange in the IDE

I was making a variable called timeOutCounter and I noticed that when I typed timeOut it turned orange in the same way as does void write begin etc. A web search turned up nothing more than people who aren't able to upload a sketch to their arduino. Can anyone shed some light onto why timeOut is like that and what its proper usage is?

timeOut is a keyword.

It's listed in the keywords.txt file of one of your libraries.

I don't see it in my IDE, so it is probably for one of the libraries you have added.

Thanks for the reply. That makes sense.