Payment at the end of a period is referred to by the singular arrear, to distinguish from past due 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.

“In arrears” means a payment is late or overdue. When you’re in arrears with a utility bill or a mortgage payment, you could face additional fees or consequences. “Paid in arrears” has a slightly different meaning. Also known as an arrearage, payment in arrears means you pay someone after they complete work.

In accounting, arrears refer to outstanding or unpaid amounts that are owed or overdue. The term is generally used to describe the status of a payment. Arrearage refers to the accumulation of unpaid amounts that were due in the past.