Phenotype is a term that is heard most often in growing. It refers to the general physical characteristics of the plant such as height, color, branching, leaf configuration down to cell structure—any markers that can be used to identify and judge the healthiness of a plant.
Pistils are part of a female plant's anatomy. On cannabis, it's identified as the little hair-like extensions on the flowers that range in color from white to red to darker orange-brown. When plants are going to be fertilized, the pistil acts to collect the male pollen. When plants are left unfertilized, as in the case of marijuana, the pistils change and can be indicators of plant ripeness.
Pre-roll is a commonly used term that refers to a pre-rolled marijuana cigarette, slangily known as a joint. Many dispensaries have pre-rolls available for purchase.