Rosin is a solid extract of resin or pitch. Resin is the sticky substance that plants often produce when an injury occurs. Other names for rosin are Greek pitch or colophony. CBD rosin contains many cannabinoids, waxes, terpenes, and other hemp plant resin components. Rosin is not soluble in water, but you can use it by scraping off bits of the hard extract and adding it to your vape or dab rig. It’s most common to smoke or vape rosin, but you can eat it directly.