Word Origin - Chronology

Chronology is the arrangement of facts and events in the order of time.
The word 'chronology' is made from two Greek words.
'chrono' meaning time and 'logos' meaning word, logic, discourse or reasoning 


A chronological list of events is a list of events arranged according to the time that they occurred.
Chronology of key events in India from 1858 to 2013

A chronograph is a watch that also includes a stopwatch. It displays different counters or mechanisms for measuring elapsed time. Counters can register seconds, minutes and hours. This gives its owner the ability to time anything he wants.

Omega Speedmaster Professional - also called Moonwatch

On April 15, 1970, a hand-wound mechanical wristwatch saved three astronauts hurtling through space in their crippled craft. The wristwatch, a chronograph, was of a design that was unchanged since the mid-1950s. Despite this, or perhaps because of this, it performed where millions of dollars worth of machinery and computers had failed. Used to time a critical engine burn to align the Apollo 13 capsule for Earth re-entry, the chronograph, an Omega Speedmaster Professional, confirmed its place as perhaps the most useful of watch complications. 

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A vintage Rolex chronometer

A chronometer is a timepiece designed to keep time with great accuracy. It has a high grade movement which has been finely adjusted at the factory and its performance tested under different temperatures, different positions, and even under water.
A chronometer is almost always accredited and certified by either the watch manufacturer or by the Swiss based standards laboratory, COSC (Contrôle Officiel Suisse des Chronomètres). Rolex is probably the world's most well known chronometer certified watch.


Mythological origin

Chronos was considered to be the personification of time in early philosophical works. Chronos was represented as a winged serpent with additional heads of a bull and a lion, and between them the face of a god.  

 

 His consort is the serpentine Ananke (Inevitability). Together they are said to have circled the world in their coils and split it apart to form the ordered universe of earth, sea and sky. Chronos was depicted in Greco-Roman mosaics as a man turning the Zodiac Wheel. Often the figure is named Aeon (Eternal Time), a common alternate name for the god.
 

Aion, the god of time, stands turning the wheel of heaven inscribed with the signs of the zodiac.  Beneath him reclines Gaia (Mother Earth) attended by the four Karpoi (Fruits) of the seasons - from left to right: Eiar (Spring), Theron (Summer), Phthinoporon (Autumn) and Kheimon (Winter).

Details of Father Time portrayed in the Rotunda clock in the Library of Congress, Washington DC

In astronomy, the planet we now call Saturn was called Khronos by the Greeks. Given that Saturn had the longest observable repeatable period in the sky, which is currently around 30 years, it was thought to be the keeper of time, or Father Time, since no other objects had been seen or recorded to have a longer period. 

Chronos was usually portrayed as an old, wise man with a long, gray beard, such as "Father Time." That is why it is often depicted as an elderly man with a long gray beard. He is commonly shown dressed in a robe, holding a scythe and an hourglass or other timekeeping device. 

You can view The Rotunda Clock by John Flanagan. in the Library of Congress Thomas Jefferson Building, Washington, D.C.

It is beautiful and full of details (description here).  

The hands are two intertwining serpents in enameled copper. The seated figure to the left is a student reading; to the right, a student writing. 

 

NOTE: The Greek God of Time, Chronos, is not to be confused with the Greek Titan God, Chronus - also known as the father of Zeus. There seems to be considerable confusion here - it definitely left me confused while I was looking up information for this post. Mythology, being what it is, it is not easy to separate the different myths from Egyptian, Greek and Roman times.