The main detail in this window shows a chalice or cup – the Latin word calix means cup. The chalice is a symbol for the Eucharist (Holy Communion) but, in this window, it is another symbol for Christ’s passion. Several times Jesus spoke of the cup of his coming suffering –
“Jesus answered, ‘You do not know what you are asking. Are you able to drink the cup that I am to drink?'” [Matthew 20:22]
“And going a little farther he fell on his face and prayed, saying, ‘My Father, if it be possible, let this cup pass from me; nevertheless, not as I will, but as you will.'” [Matthew 26:39]
“So Jesus said to Peter, ‘Put your sword into its sheath; shall I not drink the cup that the Father has given me?'” [John 18:11]

The dedication at the bottom of the window is shown in the image at far right and reads,