Origin of the term Biochar. Before there was "Biochar" there was "Agrichar". The Terra Preta community dedicated to achieving Terre Preta Nuova by reverse engineering the Amazonian Dark Earth (ADE) phenomenon coined the term "Agrichar" meaning charcoal you would want to use in an agricultural context. I miss those times, the term agrichar was easier to communicate than biochar is.
In 2006 some Australians members of the TP community saw the opportunity to make some money and commandeered the term Agrichar, trade marked it, restricted its use. The meaning of Agrichar became charcoal made by slow pyrolysis that has been enhanced in proprietary ways to perform well ag-wise. The rest of us had to come up with a new name, and biochar is the term we chose. It still upsets me! Fast forward 13 years to 2020, and the term "Agrichar" has disappeared from use.
Biochar, like the term scientist, can cover a wide range of qualities and qualifications. If my life hinges on understanding soil science, and I seek out the knowledge, and achieve soil success, am I not an accomplished soil scientist regardless of whether I paid for a degree or not? Maybe even more so? Yet some (me 15 years ago) would say, if you don't have formal qualifications you can't honestly present yourself as a soil scientist in formal contexts (teaching, public testimony, client reports) at least not without speaking to that detail. Does the term scientist become meaningless if we can't agree on one shared definition?
It's kind of the same with biochar. I take the position that if I am using charcoal to accomplish improved soil health (or animal health, or compost health), I feel perfectly fine using the term biochar regardless of feedstock, ash content, volatiles content, resulting molecular state (torrefied/amorphous/graphene), process (hydrothermal-carbonization/pyrolysis/gasification/combustion), or post process treatment (seasoning, amending, activating, charging, washing, acidifying, rinsing, crushing). However what I use as biochar often will not meet the definition of biochar established by the International Biochar Initiative, nor will it meet the definition we use among ourselves locally a tribal understanding that without inoculation, biochar is just charcoal. And there are consumer protection issues when even highly caustic black ash, even char stinky with smokey smelling tar, even charcoal made irresponsibly, can be labeled biochar, thus the need to steer folks towards IBI certified biochar products, and towards the inoculated or composted variants favored within our permaculture community as the only biochar worth having. From my perspective, I see no hard and fast rules defining what biochar as a material is and isn't, but I respect anybody who has settled on a definition that works for them, that they are comfortable with.