Time is defined as the indefinite continued progress of existence and events in the past, present and future regarded as a whole, though it cannot be physically touched or seen. To measure time and specify the order and duration of events, clocks are used to accurately track periods of less than a day, while calendars provide a mathematical system for calculating longer time periods by assigning dates.

1. TIME

2. Definition Of time :
 Time is something we deal with everyday and something
that everyone thinks they understand.
 The indefinite continued progress of existence and events
in the past, present and future regarded as whole.
 Clearly time is not an object or substance we can touch are see.

3. Measurement Of Time:
Time provides us with a measure of change by putting
dates on moments fixing the duration of events and specifying
which events happen before which other events in Order to that
some method of time measurement is need.
There are two points :
* Clock
* Calender

4. Clock:
 Clock is a physical mechanism that counts the ongoing passage
of time
 This is mainly used for more accurate time keeping and for
periods of less than a day
Calendar:
 A calendar is a mathematical abstraction used for calculating
more extensive period of time