Definition of "aye"

[…] Do that good miſcheefe, which may make this Iſland / Thine owne for euer, and I thy Caliban, / For aye thy foot-licker.

1610–1611 (date written), William Shakespeare, “The Tempest”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act IV, scene i]

The ship drove fast, loud roared the blast, / And southward aye we fled.

1834, Samuel Taylor Coleridge, The Rime of the Ancient Mariner

Huge hills and mountains of casks on casks were piled upon her wharves, and side by side the world-wandering whale ships lay silent and safely moored at last; while from others came a sound of carpenters and coopers, with blended noises of fires and forges to melt the pitch, all betokening that new cruises were on the start; that one most perilous and long voyage ended, only begins a second; and a second ended, only begins a third, and so on, for ever and for aye.

1851 November 14, Herman Melville, chapter XIII, in Moby-Dick; or, The Whale, 1st American edition, New York, N.Y.: Harper & Brothers; London: Richard Bentley

Let the Amen sound from His people again; Gladly for aye we adore Him. (Praise to the Lord, the Almighty)

1863, Translation by Catherine Winkworth