Acts 20:7, Revelation 1:10, The Lord’s Day

Acts 20:7
7On the first day of the week, when we were gathered together to break bread, Paul began talking to them, intending to leave the next day, and he prolonged his message until midnight.
Revelation 1:10
10I was in the Spirit on the Lord’s day, and I heard behind me a loud voice like the sound of a trumpet,
1960, 1962, 1963, 1968, 1971, 1972, 1973, 1975, 1977, 1995 by The Lockman Foundation
Action: What day of the week should we come together to worship? Why is that day called the Lord’s Day?