This panel would have originally been part of a much larger window. It represents the crucified Christ at the moment of death on the cross. Christ is flanked by two angels, one of which collects blood in a chalice from the wound in his right hand, a symbol of the Eucharistic wine. This potent symbol is reinforced by the scrolling vines with grapes. The window would have very likely been located behind an altar in a church where the symbolism would have resonated with the celebration of the Mass.
This image is in the public domain.