Arrears, or arrearages is a legal term for a type of debt
which is overdue after missing an expected payment. It is
also used (in the form in arrears) for payments that occur
at the end of a period.
Arrears accrue from the date on the first missed payment
was due. The term is often used to describe being late with
rent, royalties (or other contractual payments), child support,
or other legal financial obligation.
An obligation is said to be in arrears if it is past due.
"Arrears" is, further, not a late payment or charge
for late rent, but the state of being late for rent. Charges
such as this are impermissible under most Landlord/Tenant
agreements.