A Turing machine is called deterministic if there is always at most one instruction associated with a given present internal state/tape
state pair 
.
Otherwise, it is called nondeterministic (Itô 1987, p. 137).
In prediction theory, let 
be a weakly stationary process, and let 
be a subspace spanned by
the 
(with 
).
If 
is independent of 
so that 
for every 
, then 
is said to be deterministic (Itô 1987, p. 1463).
