[gilleain]

Yes, /originally/ 'Organic' meant from living matter. However, when it was discovered that urea could be synthesised in the lab, we realised that there was no real distinction between 'living' molecules and 'dead' ones ...

Nowadays, 'organic' refers to chemicals with a majority (?) carbon content. It gets a little tricky for things like diamond and graphene (both materials) or for compounds that have a lot of heteroatoms.

Oddly enough, another nucleotide base (adenine) is exactly 50:50 C:N and has been proved to be synthesised from just HCN. So is it 'half'organic' :)

[kortex]

As a (former) organic chemist, this is spot-on. "Organic" doesn't really have a strict definition, but it's not so much "majority carbon" as it is presence of a C-H and/or C-C bond. I personally don't consider diamond and graphite organic, but some do. Carbon disulfide and phosgene (COCl2) usually aren't regarded as organic. And as you mentioned, stuff with carbon and lots of carbon atoms is a grey area (looking at you, azidoazide azide, but not looking at it too hard, it might not like that).