Tick size
The smallest price increment an exchange allows a contract to move by; quotes exist only at multiples of it.
How to read the number
Tick size sets how finely a contract trades: the larger it is, the wider the narrowest possible distance between the best bid and the best offer.
When the metric lies
Ticks are counted in contract points, and a point is not a unit of currency. On index and currency contracts a result worked out from point differences alone comes out wrong.
Also known as: minimum price increment