The process of falling asleep.
The process of death or the actual death itself.
The death and assumption into heaven of the Virgin Mary.
Mary asked that the Twelve Apostles be brought to her, then fell into a deep sleep, the dormition, and died peacefully.
A Handbook of Symbols in Christian Art
It is a position anciently known, and modern experience hath allowed it for a sad truth, that absence and time, — like cold weather, and an unnatural dormition — will blast and wear out of memory the most endearing obligations; and hence it was that some politicians in love have looked upon the former of these two as a main remedy against the fondness of that passion.
Poems of Henry Vaughan, Silurist, Volume II