Tick
A tick is one change in the quoted price, and a candle is built from all the ticks inside its time period.
Definition
A tick is one change in the quoted price, and a candle is built from all the ticks inside its time period.
A busy minute can hold hundreds of ticks and a quiet one a handful. The candle keeps only the first, highest, lowest and last prices.
The word is also used for the smallest price step of a futures contract. In currency trading, the pip is the usual unit.