If you are not pursuing a career in landscape design, there is no reason to do an exhaustive search on every landscaping term.
However, by understanding a few important, phrases you can better communicate with the landscaping professionals you are working with, whether they are improving your property or if you are looking for products at your local garden store.
One gallon perennial/shrub: This is actually approx. 2.72 quarts. It is a #1 container, but the trade size is called a one gallon container.
Five gallon perennial/shrub: This is actually approx. 3.8 gallons. It is a #5 container, but the trade size is called a five gallon container.
Balled & Burlap (B&B): Balled-and-burlapped plants are transplants that have been planted, dug up, and wrapped. "Balled" referring to the root ball (that is, soil plus roots), which has been dug up, while "burlapped" refers to the wrapping material traditionally used for transporting tree and shrub deliveries.
Weed barrier: This is a fabric used to reduce the amount of weeds from growing while still allowing water, fertilizer, and oxygen to filter through to the plant.