A year is a period of twelve months or 365 or 366 days, beginning on the first of January and ending on the thirty-first of December.

A year is any period of twelve months.

Year is used to refer to the age of a person. For example, if someone or something is twenty years old or twenty years of age, they have lived or existed for twenty years.

A school year or academic year is the period of time in each twelve months when schools or universities are open and students are studying there. In Britain and the United States, the school year starts in September.

You can refer to someone who is, for example, in their first year at school or university as a first year.

A financial or business year is an exact period of twelve months which businesses or institutions use as a basis for organizing their finances.

You can use years to emphasize that you are referring to a long time.

You can refer to the time you spend in a place or doing an activity as your years there or your years of doing that activity.

If something happens year after year, it happens regularly every year.

If something changes year by year, it changes gradually each year.

If something happens year in ,year out, it happens every year without changing and is often boring.

You can say a man of his years or a woman of her years to refer to that person's age in relation to something else you are talking about.

If you say that something such as an experience or a way of dressing has put years on someone, you mean that it has made them look or feel much older.

If you say something happens all year round or all the year round, it happens continually throughout the year.

If you say that something such as an experience or a way of dressing has taken years off someone, you mean that it has made them look or feel much younger.