Day count convention
The rule for counting the fraction of a coupon period: how many days are counted in the period and how many are taken as a year.
How to read the number
Accrued interest on a given date, and therefore the cash amount of the trade, follows from the convention. Identical terms under different conventions settle for different money.
When the metric lies
The Russian market counts actual days; eurobonds often do not. Computing accrued interest for an unfamiliar issue by the familiar rule is a reliable way to disagree with the broker.
Also known as: day count basis, accrual basis