For me it is the fact that our blood contains iron. I earlier used to believe the word stood for some ‘organic element’ since I couldn’t accept we had metal flowing through our supposed carbon-based bodies, till I realized that is where the taste and smell of blood comes from.
huh, thank you for leading me to find out about organocobalt compounds, and complicate my understanding of organic/inorganic chemistry. I still that fits the simple definition of “organic” = “contains carbon” that most chemists would use, though.