Calendar n. : An orderly arrangement of the division of time, adapted to the purposes of civil life, as years, months, weeks, and days; also, a register of the year with its divisions; an almanac.

Calendar n. : A tabular statement of the dates of feasts, offices, saints' days, etc., esp. of those which are liable to change yearly according to the varying date of Easter.

Calendar n. : An orderly list or enumeration of persons, things, or events; a schedule; as, a calendar of state papers; a calendar of bills presented in a legislative assembly; a calendar of causes arranged for trial in court; a calendar of a college or an academy.

Calendar v. t. : To enter or write in a calendar; to register.

Example:
What is the best Calendar program available?

Taxonomy
Pop-Up Blocker, music, Login Form, Uncheck, shared computer, CAPS LOCK, case sensitive, free Mail, Protect your PC, Anti-Spy, weather forecasts, current conditions, Tune, sports, communications tools, instant messaging, security features, AntiVirus.

Defination from the web:
Calendar is web-based calendar to help you organize your life online, which features auto reminders, invites, and religious holidays.