Definition - What does Resin mean?
In the cannabis industry, the word resin refers to the tar-like byproduct left in a pipe or other weed paraphernalia after smoking marijuana. Resin is a waxy, sticky substance that builds up in the pipe.
In nature in general, resin is defined as a sticky, flammable, organic substance that is insoluble in water and exuded by some trees and other plants, such as fir and pine.
Hydrolife explains Resin
Cannabis resin is a combination of ash and carbon and is the equivalent to the tar in cigarettes. It is not considered healthy to smoke. Resin is extremely hard on the respiratory system and not good for the lungs.
Although it is not recommended, resin can be scraped from the pipe and used in teas, but it is so low in THC that it is generally not considered worth the effort. Other ways to consume resin would be to scrape it up and add it back to the pipe as if it were hash, or use a joint or vaporizer, but again, there is little to no value in doing so. In fact, in most cannabis cultures, smoking resin is considered a frugal, last resort when one runs out of real bud.
Indeed, resin is most often simply scraped from a pipe and discarded.