plural of year-group

(medicine, smoking) A unit for measuring the number of cigarettes a person has smoked previously; it is calculated by multiplying the average number of packs of cigarettes the person smokes per day by the number of years the person has smoked.

Alternative form of yeargroup

An informal competition among birdwatchers to determine who can see or hear the largest number of species of birds within a single calendar year and within a specific geographical area.

The period of time equal to half a year; normally referred to as 6 months, but a half-year is more exactly 182.5 days (without a leap day)

(astronomy) Great Year; one complete precession of the equinoxes, approximately 25,765 years.

The holiday commemorating (the beginning of) the new year.

In the Jewish calendar, a year of 355 days or a leap year of 385 days; perfect year.

Alternative spelling of pack-year.

Taking place in or relating to the middle of a year.