Sabbath - O.E. sabat "Saturday," observed by the Jews as
a day of rest, from L. sabbatum, from Gk. sabbaton, from
Heb. shabbath, from shabath "he rested." The Babylonians
regarded seventh days as unlucky, and avoided certain
activities then; the Jewish observance may have begun as a
similar custom. From the seventh day of the week, it began
to be applied c.1410 to the first day (Sunday), a change
completed during the Reformation. The original meaning is
preserved in Sp. Sabado, It. Sabbato, and other languages'
names for "Saturday." Sabbat "witches' sabbath" is 1652,
from the Fr. form of sabbath, a special application of the
word. Sabaoth (M.E.) is from Heb. sebaoth "hosts," plural
of saba "army," a word originally left untranslated in the
New Testament and "Te Deum" in the designation Lord of
Sabaoth, often confused with sabbath.