!!! Overview[1]
[{$pagename}] is the indefinite continued progress of existence and [events] that occur in apparently irreversible succession from the past through the present to the future.[{$pagename}] is one of the seven fundamental physical quantities [International System of Quantities]
 

[{$pagename}] is not helpful without a [Date] and may be referred to as [DateTime][{$pagename}] is a fact of life that not all events in our universe happen concurrently - instead, there is a certain order. Defining a [{$pagename}] coordinate or defining [{$pagename}], the way physicists do it, is to define a prescription to associate with each [event] a number so as to reflect that order - if event B happens after event A, then the number associated with B should be larger than that associated with A. !! [Proper Time]
[Proper Time] along a timelike world line is defined as the time as measured by a clock following that line and is thus independent of coordinates, and is a Lorentz [scalar].

[Proper Time] could be described as the time on your wrist watch.

Perhaps of greater interest is the Proper Time Interval which is the interval between any two [events].

!! [now]
[now] (or [Simultaneity]) is something we rarely think about - we just accept it as a fact of life. However, thinking matters through, it isn't obvious at all how one can determine whether or not two events at two different locations happen simultaneously, or not.

!! More Information
There might be more information for this subject on one of the following:
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* [#1] - [Time|Wikipedia:Time|target='_blank'] - based on information obtained 2018-04-23-