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. (See SABBATH.)
BIBLE DICTIONARY + WORD STUDY
Lord’s day
Historical dictionary entry
Scripture references
Source: Easton’s Bible Dictionary (1897). Historical dictionary wording reflects the scholarship and language of its era.