Shatter is an extract made from the cannabis plant that yields very high levels of THC, often 70-95%. CBD levels are much lower, and the result is often psychedelic with only a dose the size of a grain of rice.
Concentrates refer to the product of a cannabinoid extraction process that often uses a solvent (H2O, C2O, butane, alcohol, etc). The goal of concentrates is to eliminate all plant matter and extract the resin glands from the plant matter. Concentrates are made by mixing the plant matter with a solvent then strained or purged to remove plant matter and any remaining solvents from the product.