Drainage basin: The area drained by a river and its tributaries. A drainage basin is considered to be an open system because water can be added or lost from a drainage basin. Source: The beginning of a river. A river may have multiple sources.
Milk thistle (Silybum marianum) is a thorny plant presenting decorative leaves with a white pattern of veins and purple flower heads. The plant originates from mountains of the Mediterranean region, where it forms scrub on a rocky base.
Hypernyms (milk thistle is a kind of...): bush; shrub (a low woody perennial plant usually having several major branches) Hyponyms (each of the following is a kind of milk thistle): milkweed; Sonchus oleraceus (annual Eurasian sow thistle with soft spiny leaves and rayed yellow flower heads) Holonyms (milk thistle is a member of...):