A symbol that gains entry into a state. Each state has only one valid accessor. The accessor array gives the accessor symbol numbers for the states. This permits the terminal and nonterminal transition lists to contain only the state numbers. So when making a transition you must consult the accessor array to see if the token is valid. Several states may have the same accessor, but each state only has one accessor. The terminal accessor numbers are positive and the nonterminal accessor numbers are negative. 0 is the first terminal symbol number.