Easton’s Bible Dictionary

Lord’s day

Only once, in Rev. 1:10, was in the early Christian ages used to denote the first day of the week, which commemorated the Lord’s resurrection. There is every reason to conclude that John thus used the name.

Lord'S Day in Nave’s Topical Bible0 references, arranged by theme

Easton’s Bible Dictionary (1897), public domain. Text via Theographic Bible Metadata, CC BY-SA 4.0.