1. 日历;月历
    A calendar is a chart or device which displays the date and the day of the week, and often the whole of a particular year divided up into months, weeks, and days.

    e.g. There was a calendar on the wall above, with large squares around the dates.
           上面的墙上挂着日历,日期上画着大大的方框。

2. 历法
    A calendar is a particular system for dividing time into periods such as years, months, and weeks, often starting from a particular point in history.

calendar的意思

    e.g. The Christian calendar was originally based on the Julian calendar of the Romans.
           公历最初是以罗马人的儒略历为基础制定的。

3. (某一组织、团体或个人的)日程表，纪事表，大事一览表
    You can use calendar to refer to a series or list of events and activities which take place on particular dates, and which are important for a particular organization, community, or person.

calendar什么意思

    e.g. It is one of the British sporting calendar's most prestigious events...
           这是英国体坛大事表上最负盛名的赛事之一。
    e.g. Franklin joined her and the children whenever his crowded calendar allowed...
           只要能从百忙之中抽出空,富兰克林就会陪在妻儿身边。