THC-O

THC-O is the short name for THC-O-acetate. An acetate group is attached to the THC molecule. Older notes also print THCO or THC-O-acetate. Acetate esters of cannabinoids appear in mid-century chemistry papers, as named derivatives, long before the letters showed up on modern product labels. The recent use of THC-O is that older ester name on a retail label. Delta-9 lives on the THC page. A label that says THC-O or THC-O-acetate is this ester.