Today's Word of the Day means...
"Greek planetary names [for the days of the week] ... are attested for the early centuries of our era, but their use was apparently restricted to certain circles; at any rate they never became popular. In Rome, on the other hand, the planetary names became the established popular terms, too strongly intrenched to be displaced by the eccl[esiastical] names, and spreading through most of western Europe." [Buck]
From the beginning, time was divided into weeks, each consisting of six days of working and one of rest (Gen. 2:2, 3; 7:10; 8:10, 12; 29:28). The references to this division of days becomes afterwards more frequent (Ex. 34:22; Lev. 12:5; Num. 28:26; Deut. 16:16; 2 Chr. 8:13; Jer. 5:24; Dan. 9:24-27; 10:2, 3). It has been found to exist among almost all nations.
period of seven days, a unit of time artificially devised with no astronomical basis. The origin of the term is generally associated with the ancient Jews and the biblical account of the Creation, according to which God laboured for six days and rested on the seventh. Evidence indicates, however, that the Jews may have borrowed the idea of the week from Mesopotamia, for the Sumerians and the Babylonians divided the year into weeks of seven days each, one of which they designated a day of recreation.