Gary Hampton quotes Hugo McCord on the phrase “the Lord’s day” in Rev. 1:

McCord says, “It so happens that the word “Lord’s” (Kuriakes, pertaining to the Lord) appears only twice in the New Testament, once in referring to the Lord”s supper (1 Corinthians 11:20), and once in referring to the Lord”s day (Revelation 1:10). Apparently these two, the supper and the day, belong together.”