I can’t speak specifically to the context of whether the term “weekend” would have been familiar to an aristocratic woman in Edwardian England, but I can address some of the related questions about the history of the week, as well as recommending two books aimed at a general audience on the history of the week and weekend— Witold Rybczynski’s ‘Waiting for the Weekend’ and Craig Harline’s ‘Sunday: A History of the First Day from Babylonia to the Super Bowl’.

The seven-day cycle is ancient, with scholarly disagreement over whether the Israelites adapted it from the 28 Babylonian lunar month which was subdivided into 14 day and 7 day periods for some ritual purposes, or whether it developed independently in each tradition. In either case a seven-day cycle was also adopted by the Persians, and may have spread into the Hellenistic world, where the 7 day cycle was used astrologically (which may be how the days gained the association with certain planets). Rather than a seven day cycle, the Roman republic and early Empire used instead a system where every 8th day was a market day. The seven-day week only became the dominant way to track days globally due to the spread of Christianity, which kept the seven day cycle of Judaism though shifting worship at some point early on from the Sabbath to the first day of the week. Since the 7 day cycle was also adopted by Islam (though with communal prayers on Friday) between Christian and Islamic evangelization, trade, and conquest, it spread throughout the world alongside the Abrahamic traditions. Other methods, including a 10-day cycle in Republican France, and both 5 and 6 day labor cycles in post-revolutionary Russia, have been attempted occasionally by regimes attempting to break free of the religious associations of the 7 day week but none has remained in consistent use or become a dominant calendrical system for public use in spite of governmental efforts.

The 2-day weekend, however, was a fairly late arrival, coming into being as more and more laborers shifted from seasonally cyclical agricultural production into more continuous industrial and bureaucratic work environments where labor shifts were organized in a systematic fashion. The “weekend” developed alongside a formal working week— in the 17th and 18th century, artisans in England and its colonies referred to skipping work on the 2nd day of the week as “keeping Saint Monday” by enjoying an “extra” day of rest, sometimes spending wages, which were often distributed on Saturday, on entertainment before beginning another week of labor. Rybczynski notes that Saturday became a half-day at some factories in nineteenth century Britain as management sought to encourage employees to work on Monday, and the Saturday-Sunday weekend grew out of expanded recreational opportunities due to the larger number of workers off for at least part of both those days.

But obviously, even with increased standardization, there have always been laborers whose schedules don’t provide a consistent weekend, either because they have a weekly day off outside of the Sat-Sun weekend, or because their days off don’t remain the same week to week (see the schedules of firefighters and truckers, for instance, which are measured in hours on/hours off rather than in days) and there are also persons who due to wealth or privilege don’t participate in the labor market at all, including the ‘refined’ women of high station in nineteenth century Britain. Thus, the dowager countess’ comment about the weekend may reflect her sense of superiority to individuals who had to work for a living, combined with the fact that some servants would be working each day of the week to keep an estate of that size operating, and thus for both the noble and common residents of the Abbey, the “weekend” as such happened to other people.