Year is a unit of time that is commonly used to measure the duration of an Earth's orbit around the sun. However, there are several synonyms that can be used interchangeably with the word year. These synonyms include annum, calendar year, fiscal year, solar year, and leap year. Annum is typically used in formal or technical settings, whereas calendar year refers to the period from January 1st to December 31st. A fiscal year is the 12-month period used by businesses for financial reporting, while a solar year is the time it takes for the Earth to orbit around the sun. Lastly, a leap year is a year that contains an additional day, February 29th, to align our calendar with the Earth's orbit.