It is the day when Christians commemorate Jesus Christ’s crucifixion. So why is it called Good Friday? According to the Bible, the son of God was flogged, ordered to carry the cross on which he would be crucified and then put to death.
The first of these theories is that Good Friday is called Good Friday because, Christians believe, there is something very good about it: It is the anniversary, they say, of Jesus suffering and dying for their sins. … The second theory is that the Good in Good Friday derives from God or “God’s Friday.”
The second theory is that the Good in Good Friday derives from God or “God’s Friday.” Wikipedia, for example, puts this theory forward citing a 1909 entry in The Catholic Encyclopedia. In a separate article on the same subject, the Huffington Post does the same. However, there seems to be no basis for this etymology. “The origin from God is out of the question” according to Anatoly Liberman, a professor at the University of Minnesota who studies the origins of English words. (Liberman also told me that English speakers have a long history of speculating about a relationship between the word good and the word godwhere there is none.) The linguist and lexicographer Ben Zimmer agreed, noting that the German for Good Friday isn’t actually “Gottes Freitag” (“God’s Friday”), as the Catholic Encyclopedia suggests, but rather Karfreitag (“Sorrowful Friday”). “None of the early examples in the Oxford English Dictionary imply that it started off as God’s rather than Good, so I don’t really see this as more than speculative etymology,” Zimmer added.