Most fitting word for a time interval with specific start and end? [duplicate]

If I'm talking about an appointment of a specific time and duration, what's the most fitting word? "Time span", "time range", "time interval"? Anything else?

By "most fitting" I mean that it should suggest to the listener that I'm talking about the interval between specific dates, not about a duration or period.

Word for a moment in time defined with beginning and end only has a rather pragmatic answer concerning programming.

Online dictionaries give contradicting definitions, for example for "time interval":

http://www.vocabulary.com/dictionary/time%20interval "a definite length of time marked off by two instants."

http://www.thefreedictionary.com/time+interval "Duration of a segment of time without reference to when the time interval begins or ends."

Solution 1:

Perhaps he is suggesting at 'Time schedule' or 'time calendar'.

I think,"TIME SLOT" would be most befitting which actually,amongst others, goes to mean the allocated time for an aircraft's departure or arrival at an airport's runway.