In the literal sense it is chocolate made from the raw cacao bean and made by a chocolate maker not a chocolatier.

However, the term “bean to bar” has evolved past the literal meaning, and has also become a synonym for:

High quality chocolate (quality refers to the quality of the cacao bean, quality of other ingredients, and quality of the methods used to produce it)

Made from fine cacao (cacao that is not too bitter or acidic, with a depth of aromas beyond “cocoa”)
Most often, but not always, associated with fairly or directly traded cacao (but not always certified due to costs and bureaucracy)

A focus on fine flavour & texture, transparency (trade, ingredients, process)

So when someone refers to chocolate as “bean to bar”, they are often suggesting all of the above. Sometimes people refer to it as “craft” or “fine” chocolate as well.