De profundis (Out of the depths). Psalm 129 in the Vulgate (following the Septuagint) and 130 in the Eng. Authorized and Revised versions (following the Hebrew). It is one of the 7 Penitential Psalms (see psalm) and, attached to its traditional plainsong, has a place in the Office of the Dead of the RC Church. It has been set by composers many times.

de profundis a heartfelt cry of appeal expressing one's deepest feelings of sorrow and anguish, from the opening words (Latin, ‘from the depths’) of Psalm 130. De Profundis was the title of Oscar Wilde's prose apologia, begun while he was in prison as a letter to Lord Alfred Douglas, and published in 1905.