In the Holy Week or Passion Week of Jesus, today is called Good Friday. When you understand that this is the day that Jesus was crucified it’s hard to make the claim that it was in any way good but according to GotQuestions.org this is the reason it is commonly called that:
What is “good” about Good Friday? What the Jewish authorities and Romans did to Jesus was definitely not good—it was evil (see Matthew chapters 26—27). The answer lies in the etymology of the English word good. In Middle English, the adjective gọ̄d held the sense of being “holy” or “sacred.” Before standardized spelling, the word also appeared as gode, goed, gude, goid, and good (Middle English Dictionary, Regents of the University of Michigan, 2025). The connotation of being “holy” is carried through in modern observances of “Good” Friday. (What is Good Friday / Holy Friday? | GotQuestions.org)
This day is holy in the sense that we set it apart from other days because we remember that Jesus, who was arrested and tried overnight in a sham, illegal trial, was then beaten and tortured and nailed to a wooden cross to die. The end result was, of course, good for us (as we understand the word “good”) but it was a dark day in history.
I encourage you to read about it in all four Gospels and meditate on it as you go about your day. Matthew 27; Mark 15; Luke 22:66—23:56; John 18:28—19:37