What does "rest day" mean?

A day spent resting from work or any other activity.

What is a synonym for "rest day"?

Common synonyms include: day of rest, sabbat, sabbath, sabbaths, sabbatia, shebat.

noun

noun ·Rare ·Advanced level

Noun

1
A day spent resting from work or any other activity.
"With overtime, rest day working and other payments, a union source said many drivers can expect to earn well in excess of £75,000."
2
a day set aside for rest wordnet

"With overtime, rest day working and other payments, a union source said many drivers can expect to earn well in excess of £75,000."

Possibly a continuation of Middle English resten-dei, restandæȝ, from Old English restendæġ (“day of rest; Sabbath”).