1historical Any one of the six years in a sabbatical cycle during which agricultural work is done, as opposed to a sabbatical year.
2The part of a year allotted to or spent at work, or during which a person works (excluding holidays, seasonal breaks, etc.).
3In plural The part of life during which a person (typically) works, especially as opposed to being of school age or in retirement.
Early 18th century. From working + year.