I was navigating about this text I'm currently reading and I grew curious what exactly is meant by
Location in the context of a kindle book. Is this essentially a word or character count?
If you look at the screen shot below I outlined in red the section of the UI that points out the text progress. There it states
Page 14 × Loc 358 at the slider bar, and in the status bar
5% - Page 14 of 393 - Location 358 of 7091