What does "the day of the Lord" in Thessalonians refer to?

What is being referred to by "the day of the Lord" in 1 Thes 5:1 and 2 Thess 2:2, the rapture or second coming?

2 Thessalonians 2:1

NASB - ¹ Now we request you, brethren, with regard to the coming of our Lord Jesus Christ and our gathering together to Him.

Clarify • Share • Report • Asked March 21 2016 • Lorraine DeAngelis