Part of Speech: Noun

Definition: the ebb [usually singular] the period of time when the sea flows away from the land the ebb tide

Source: Oxford Dictionary

Found in: Pity me not because the light of day “Nor that the ebbing tide goes out to sea,…” (line 6)

Meaning in Context: Ebbing is used to describe the movement of the ocean coming in and out, in this case out which may be symbolic for time or a general sense of something leaving.