A parasite is an organism that lives in or on another organism and obtains nutrients from it. The organism that supplies the nutrients is known as the host. Dodder is classified as a parasite because it absorbs nutrients from its host. It has no roots when it's mature and gets food, water, and minerals from the host. Mistletoe is classified as a hemiparasite. (The prefix "hemi" means half.) Mistletoe absorbs water and minerals from its host, but makes its own food via photosynthesis.