predictable process

A stochastic process is predictable if its value at time $t + 1$ is fully determined by information available at time $t$.

Any fully deterministic process (where $x_{t + 1}$ is a deterministic function of $x_t$) is obviously predictable, but predictability is a weaker condition, because we are allowed to use other information from whatever probability space we're using. For example, a roulette betting strategy is predictable if the bet at time $t + 1$ is determined by the outcomes up to time $t$, even if those outcomes (and thus the sequence of bets that depend on them) are themselves stochastic.