Tick
A tick is the smallest price change allowed on an instrument, mostly used on futures. Each tick has a fixed cash value.
On a futures market, price does not move continuously: it steps in minimum increments set by the exchange, called ticks. On the E-mini S&P 500, one tick is 0.25 point, or $12.50 per contract. On the 100-ounce COMEX gold future, a $0.10 tick is worth $10.
Thinking in ticks lets you calculate your risk exactly: an 8-tick stop on the E-mini is $100 per contract.
The word also means each individual price update. A tick chart draws a new bar every N price changes, regardless of how much time has passed.
See also