Is it slander or defamation if a coworker tells other coworkers & posts on Facebook & texts other people about someone they work with does nothing that she has to do every thing when the truth is she is the one that does nothing every one at work & our boss knows the truth I also found out that she has don something on Facebook that I don‘t think I can mention on here & that is against Facebook policy I am the one that she is talking about she has only been there for about 6 months give or take a little no one wants to work with her because of the trouble she has been causing she is part time I am full time I think she is trying to get a full time person fired so she can have full time the company I work for does not have any more full time positions in the area I work I have tried to be nice to her & every one else has to does not work with her I have tried to help her with things so she doesn't get in trouble thin she says I am having at her she has been shown how to do things then she tells every one that she was not shown is there any thing that can be don about her telling people on Facebook & at work lies about me

Slander maybe. But you haven't suffered any real damage so there's not much you can do. Based on your side of the story only she sounds like she behaves this way at all of the jobs she has had and I bet she doesn't last very long. So just ignore her and do your job.

Also does your company have a policy on Social Media? That could be an avenue for you.

If she mentions the company name on Facebook, ask your boss or HR department.
A lot of companies are cracking down on remarks made online. But it would have to include them, not just you.
I doubt that you will get anywhere with a personal lawsuit. You have to prove monetary loss and it will cost you more than it's worth.
You could calmly tell her that you are planning to over the Facebook comments, just to see if it scares her.
If your company handles it, let that be it.

Yes my company has a policy for social media & she has had the company name in some of her posts but not with me at the same time she has not put spasific names names down ether but every one knows who she is talking about I did have proof at one time my boss has told her at least 4 times not to post things on Facebook but she has started texting people about it now we have a new employee that she sent the text to & he told me something that she has don to hem & his room mate on Facebook I talked to my mom about all of it she thinks the new employee his room mate & I should go to the police should we go to the police

Why would you go to the police? What would you expect them to do? I don't see a crime being committed here.

Why would you go to the police? What would you expect them to do? I don't see a crime being committed here.

To see if there is any thing that they can do

There is nothing the police could do, this is a civil matter, not a criminal matter.

Agreed, you seem confused between criminal matters (which are what police handle, and pass on to the Criminal Court by way of district attorneys) and civil matters, which you have to handle on your own or with a lawyer, in Civil Court.
But you are also confused about this whole matter. You now say that your name isn't mentioned, but everyone knows who she is talking about. That isn't even a civil case. And even if she does mention your name, you aren't going to get monetary damages in court!
You need to deal with this like an adult, by ignoring most of it, by calmly confronting her at work, and by telling your employer, bringing as many other employees as you can with you. When you do so, keep it short. Summarize. They don't want to hear every little incident. Just say that she is out for your job and stirring up trouble with everyone.

Is it slander or defamation if ... every one at work & our boss knows the truth ...

No. Obvious fiction is not defamation.