In finance, arrears (or arrearage) is a legal term for the part of a debt that is overdue after missing one or more required payments.
For example, a housing tenant who is obliged to pay rent at the end of each month is said to pay rent in arrear, while a tenant who has not paid rental due for 30 days is said to be one month in arrears.
The dividends in arrears must be disclosed in the notes (footnotes) to the financial statements.
The word arrears means "end of period" when referring to annuities (an annuity is a series of equal amounts occurring at equal time intervals, such as £1,000 per month for 20 years).
The same distinction holds for other interest rate derivatives, e.g. caps, floors and swaptions.