I keep on hearing this word…what excatly does it mean? I have ideas but I wanna make sure…could someone please enlighten me?

ar·rears ( P ) Pronunciation Key (-rîrz)
An unpaid, overdue debt or an unfulfilled obligation.
The state of being behind in fulfilling obligations: an account in arrears.

Generally refers to taxes in R.E.

Tax payments are 6 months in arrears. i.e., you pay jan. - june taxes paid in June and june-jan taxes in jan.

arrears~ Can also mean payments it is anything with a past due amount!