I think the most useful definition (since beer terms are so vague anyhow), is something like "beer made at a low primary fermentation temperature followed by a

I think the most useful definition (since beer terms are so vague anyhow), is something like "beer made at a low primary fermentation temperature followed by a long, even colder secondary fermentation, aka 'lagering'". Limiting yourself to barley, wheat, and hops like modern German law does is too much prescription and not enough description.