In poker, the term heater describes a very successful run of results over a relatively short period. In addition to describing a prolonged winning streak, a heater can also describe an exceptionally good run of cards during an individual session.
For example, you could say - “John is on a heater since he won five tournaments in the last two weeks.” In this case, the term heater describes a player’s unexpectedly good winning streak.
On the other hand, you could also say that you were on a massive heater during your last home game, meaning that you got dealt a lot of good cards and made a lot of strong hands, winning you many big pots.
Another term that poker players use to describe a heater is upswing. All of them are synonymous and refer to having exceptionally good luck at the tables, leading to unexpectedly positive results.