A definition of poetry can only determine what poetry should be and not what poetry actually was and is otherwise the most concise formula would be: Poetry is that which at some time and some place was thus named.
Pity the selfishness of lovers: it is brief a forlorn hope it is impossible.
When one by one our ties are torn and friend from friend is snatched forlorn when man is left alone to mourn oh! then how sweet it is to die!