"calendars" in the noun sense
a system of timekeeping that defines the beginning and length and divisions of the year
a list or register of events (appointments or social events or court cases etc
"I have you on my calendar for next Monday"
a tabular array of the days (usually for one year)
"calendars" in the verb sense
enter into a calendar
Source: WordNet® (An amazing lexical database of English)
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