Meaning : A system of timekeeping that defines the beginning and length and divisions of the year.
Meaning : A list or register of events (appointments or social events or court cases etc).
Example :
I have you on my calendar for next Monday.
Meaning : A tabular array of the days (usually for one year).
Calendar ka meaning, vilom shabd, paryayvachi aur samanarthi shabd in Hindi. Calendar ka matlab kya hota hai?