What does Coxiella Burnetii mean in plain English from Latin?

It looks to me as though the name comes from a couple of scientists -- named Cox and Burnet. It's not uncommon to "Latinize" surnames this way to honor scientists who may have worked on an issue.

And, in fact, I am correct, as it turns out. You could have discovered this by simply googling. There's a Wiki article:

As with may scientific names, this one is derived from the name of scientists involved in unravelling the mystery of Q-Fever.

quote from the Wiki-article listesd as source below:

The pathogen of Q fever was discovered in 1937, when Frank Macfarlane BURNET and Mavis Freeman isolated the bacterium from one of Derrick’s patients.It was originally identified as a species of Rickettsia. H.R. COX and Gordon Davis isolated it from ticks in Montana, USA in 1938