One of the characteristics of language is that it has enabled humans to live in a four-dimensional world in which time is the fourth dimension. In the Scientific American publication, A Question of Time: The Ultimate Paradox, John Matson writes:
“Physicists often describe the fabric of the universe we inhabit as four-dimensional spacetime, comprising three dimensions of space and one of time.”
In another article in A Question of Time: The Ultimate Paradox, Paul Davies writes:
“All of eternity is laid out in a four-dimensional block composed of time and the three spatial dimensions.”
Language allows humans to talk and to think about the past and the future as well the present. Paul Davies reports:
“In daily life we divide time into three parts: past, present and future. The grammatical structure of language revolves around this fundamental distinction.”
As human societies became more complex and early civilizations—societies with agriculture, cities, and writing—developed, there was a need for a more formal way of organizing community activities, religious ceremonies, and other public events. By about 5,0000 years ago, the early civilizations in Babylon and Egypt had developed calendars based on the natural cycles which they had observed. In A Question of Time: The Ultimate Paradox, William Andrews reports:
“They based their calendars on three natural cycles: the solar day, marked by the successive periods of light and darkness as the earth rotates on its axis; the lunar month, following the phases of the moon as it orbits the earth; and the solar year, defined by the changing seasons that accompany our planet’s revolution around the sun.”
Day/Night
The rising and setting of the sun marks time into two basic units: day and night. In an article in A Question of Time: The Ultimate Paradox, Antonio Damasio writes:
“In the course of evolution, humans have developed a biological clock set to this alternating rhythm of light and dark.”
In another article in A Question of Time: The Ultimate Paradox, Karen Wright reports:
“The circadian clock—from the Latin circa (‘about’) and diem (‘a day’)—tunes our bodies to the cycles of sunlight and darkness that are caused by the earth’s rotation. It helps program the daily habit of sleeping at night and waking in the morning.”
With regard to English etymology, the word day is from the Old English dӕg meaning both “day” and “lifetime” which comes from the Proto-Germanic *dagaz. Sources disagree on the Proto-Indo-European stem: some feel that it is *agh- meaning “a day” as in a span of time, while others show it as *dhegh- meaning “time when the sun is hot.”
The English word night comes from the Old English niht meaning “night, darkness” and is from the Proto-Germanic *nakht- which is from the Proto-Indo-European *nekwt-.
Week
In many cultures, days are grouped into longer units of time, such as the week. The time frame of a week is a cultural designation—i.e. human-made—rather than be a natural time division. In his book When Languages Die: The Extinction of the World’s Languages and the Erosion of Human Knowledge, David Harrison writes:
“But the week is not a natural unit based on patterns observable in the cosmos or bio-rhythms. The week is not perceptually detectable and does not map nearly either onto the lunar year or the solar month.”
In terms of language, a designation for a week is missing in most languages. The English word week is from the Old English wuca or wice which is from the Proto-Germanic *wikon which originally indicate a sense of turning or succession. The Proto-Indo-European root is *weik- meaning “to bend, wind.” There is some speculation that the Proto-Indo-European may have referred to an earlier time division, perhaps a half month. There is no evidence that German-speaking people had a seven-day week or similar time unit prior to their contact with the Romans.
With regard to religion, the idea of weekly ceremonies seems to be primarily associated with the Abrahamic religions. In modern Western societies, however, where the week is firmly established as a way of regulating temporal activities, many non-Western religious traditions now due weekly ceremonies.
Month
Many cultures, perhaps most, have a time period which is based on the lunar cycle. It takes 28 days for the moon to go from full back to full. In many cultures there is a celebration, a kind rite of passage, marking the end of one year and the beginning of the new year.
The English word month is from the Old English monað with is from the Proto-Germanic *menoth- meaning “moon.”
Year
The year is, of course, the length of time it takes the earth to go around the sun. For most people, however, the year is a cycle of seasons. In many cultures there is a celebration, a kind rite of passage, marking the end of one year and the beginning of the new year. In modern cultures, the December 31-January 1 designation is purely arbitrary and has nothing to do with the seasons. In many cultures, such as ancient Babylon, the year ended and began with the vernal equinox which marked the beginning of spring. For agricultural societies, this marked the beginning of the planting season.
In terms of planting or astronomy, January 1 makes no sense as the starting point for the new year. As the Catholic Church gained power in Europe it sought to eradicate all pagan holidays. Many of the pagan holidays were timed to celebrate equinoxes and solstices—naturally observable seasonal events. Pagan Romans celebrated Natalis Solis Invicti—the birthday of the Invincible Sun God Mithras—about the 25th of December and so, rather than banning this celebration, the church simply proclaimed as the birthday of Jesus. To prevent an pagan-type celebration of a new year in the spring, January 1 was proclaimed the Feast of Christ’s Circumcision and the beginning of the new year. It wasn’t, however, until about 1600 that January 1 was widely accepted as the beginning of the new year.
The English word year is from the Old English gear which is from the Proto-Germanic *jeram which is from the Proto-Indo-European root *yer- meaning “year, season.”
More about English
Origins of English: Kinds of meat
Origins of English: Good and Evil
Origins of English: Place Names
Origins of English: The Anglo-Saxon Roots
Origins of English: The Normans
Origins of English: Phrases and Anatomy
Origins of English: Forks, Spoons, Knives
Origins of English: Telling Time