Hash is short for hashish, which is derived from cannabis plants and can be used for consumption or medication. Production involves the removal of the plant's trichomes by sieving or filtering. Once the cannabinoid-laden powder has been collected, it is typically pressed and ready to be used. Hash ranges in potency, but is generally stronger than straight flowers since everything but the active part of the plant has been removed. A similar concentrated product can also be produced chemically using a solvent; however, this product is commonly referred to as hash oil or "honey oil."
An heirloom refers to a cannabis strain that was taken from its native homeland and propagated in another geographical location.
Hemp is a fibrous product that can be produced from the male cannabis plant and can be used in the manufacture of rope, paper, beauty products, and a vast array of other products. Hemp plants have no value as a drug since they are males. However, they are still considered illegal in the United States.
Hybrid refers to a plant that is genetically a cross between one or more separate strains of cannabis. Hybrids can happen unintentionally, but they are usually bred specifically to combine desired traits of the original plants. Most marijuana on the market today is some form of hybrid.
Hydroponics refers to a system of gardening that does not use soil. Plants are grown in water and receive their nutrients from the addition of solutions rather than soil. For growers, hydroponic advantages include more control over nutrient intake and stability. In terms of marijuana production, plants grown hydroponically are sometimes said to have cleaner, more distinct flavors.