Generally the bones translation (the translation you store, lerp) is local/relative to the bones parent bone, if there is no parent bone its local = world. You would transform a bones local transform by its parents world transform to create its world transform, and then use the result for skinning.
As for blenders terminology Im not sure, local = tail? maybe? I find the term bone confusing, it implies two end points, when modeling packages tend to view them as transform nodes with an optional parent node. Nothing says you cant have a single bone-node-transform, attach a model to it and animate it.