American Dictionary
Define dictionary terms easily — search for "example", "dictionary", "language", or "word" in our powerful online English dictionary.
Define dictionary terms easily in our powerful online English dictionary.
Searching for...
No matching words found
Try a different search term or browse the dictionary
the natural system that prevents diseases spreading from one type of animal or plant to another. This is often referred to in relation to BSE (=a disease of cows) spreading to humans in the form of CJD (=a brain disease in humans).