A moment () is a

medieval In the history of Europe, the Middle Ages or medieval period lasted approximately from the 5th to the late 15th centuries, similarly to the post-classical period of World history (field), global history. It began with the fall of the West ...

unit of time A unit of time is any particular time interval, used as a standard way of measuring or expressing duration. The base unit of time in the International System of Units (SI), and by extension most of the Western world, is the second, defined as ...

. The movement of a shadow on a

sundial A sundial is a horology, horological device that tells the time of day (referred to as civil time in modern usage) when direct sunlight shines by the position of the Sun, apparent position of the Sun in the sky. In the narrowest sense of the ...

covered 40 moments in a solar hour, a twelfth of the period between

sunrise Sunrise (or sunup) is the moment when the upper rim of the Sun appears on the horizon in the morning, at the start of the Sun path. The term can also refer to the entire process of the solar disk crossing the horizon. Terminology Although the S ...

and

sunset Sunset (or sundown) is the disappearance of the Sun at the end of the Sun path, below the horizon of the Earth (or any other astronomical object in the Solar System) due to its Earth's rotation, rotation. As viewed from everywhere on Earth, it ...

. The length of a solar hour depended on the length of the day, which, in turn, varied with the

season A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's axial tilt, tilted orbit around the Sun. In temperat ...

. Although the length of a moment in modern

second The second (symbol: s) is a unit of time derived from the division of the day first into 24 hours, then to 60 minutes, and finally to 60 seconds each (24 × 60 × 60 = 86400). The current and formal definition in the International System of U ...

s was therefore not fixed, on average, a medieval moment corresponded to 90 seconds. A solar day can be divided into 24 hours of either equal or unequal lengths, the former being called natural or equinoctial, and the latter artificial. The hour was divided into four (quarter-hours), 10 , or 40 .

Usage

The unit was used by medieval computists before the introduction of the

mechanical clock A clock or chronometer is a device that measures and displays time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month, and the ye ...

and the

base 60 Sexagesimal, also known as base 60, is a numeral system with sixty as its base. It originated with the ancient Sumerians in the 3rd millennium BC, was passed down to the ancient Babylonians, and is still used—in a modified form—for measuring ...

system in the late 13th century. The unit would not have been used in everyday life. For medieval commoners the main marker of the passage of time was the

call to prayer A call to prayer is a summons for participants of a faith to attend a group worship or to begin a required set of prayers. The call is one of the History of telecommunication, earliest forms of telecommunication, communicating to people across gre ...

at intervals throughout the day. The earliest reference found to the moment is from the 8th century writings of the

Venerable Bede Bede (; ; 672/326 May 735), also known as Saint Bede, Bede of Jarrow, the Venerable Bede, and Bede the Venerable (), was an English monk, author and scholar. He was one of the most known writers during the Early Middle Ages, and his most fa ...

, who describes the system as 1 solar hour = 4 = 5 lunar = 10 = 15 = 40 . Bede was referenced five centuries later by both

Bartholomeus Anglicus Bartholomaeus Anglicus (before 1203–1272), also known as Bartholomew the Englishman and Berthelet, was an early 13th-century scholasticism, Scholastic of Paris, a member of the Franciscan order. He was the author of the compendium ''De propri ...

in his early encyclopedia (''On the Properties of Things''), as well as

Roger Bacon Roger Bacon (; or ', also '' Rogerus''; ), also known by the Scholastic accolades, scholastic accolade ''Doctor Mirabilis'', was a medieval English polymath, philosopher, scientist, theologian and Franciscans, Franciscan friar who placed co ...

, Note the distinction between and , as well as the introduction of the , the precursor to the modern minute. by which time the moment was further subdivided into 12 ''ounces'' of 47 ''

atoms Atoms are the basic particles of the chemical elements. An atom consists of a nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished from each other ...

'' each, although no such divisions could ever have been used in observation with equipment in use at the time.

References

{{wiktionary, moment Units of time zh:时刻 Time measurement systems Time