Bot
A bot is software that plays online poker automatically.
The simple explanation
A bot is a computer program that plays online poker without a human at the controls. Most sites ban bots because they give an unfair edge: they can play all day, never tire and never tilt. Playing with a bot is against the rules, and sites close accounts that use them.
A closer look
Bots can beat many low-stakes games, and even a bot that wins little can make money from rakeback. The larger danger is a network of bots working together, which is a form of collusion. Sites fight bots with behavior analysis, with captchas and with limits on multi-accounting. Real-time assistance software, which helps a human decide during a hand, is also banned because it has a similar effect.
A practical example
A site bans an account after finding that a program was making its decisions.
Full explanation
A bot is software that plays online poker automatically.
A bot is a software app that plays online poker. The word is short for robot. Such programs exist and can beat many low-stakes games, but using them is against the rules of every large site.
A bot does not tire, does not tilt and can play many tables at once. That makes it dangerous for honest players, who lose money to opponents they cannot beat in stamina.
A team of bots is more serious still. They can share information and play against humans as a single entity, which is collusion.
Sites detect bots by looking at how players act: speed of decisions, patterns of play and the hours they play.