What is the correct definition of coNP/poly?
Recall that a decision problem is a language $L \subseteq \{0,1\}^*$.  (This is the language of all words $w$ such that the answer to the yes/no question is &quot;yes&quot;.)
In this context, a Turing machine solves a decision problem $L$ if $L$ is the language accepted by that Turing machine.  In other words, when run on input $w$, the Turing machine halts and accepts if $w \in L$, and halts and rejects if $w \notin L$.