If the key has several choices it is described as polychotomous or polytomous.

We defined one "accepted" response to each item to serve as a basis from which to examine both dichotomous and polychotomous responses.

Polychotomous key refers the number of alternatives which a decision point may have in a non-temporal hierarchy of independent variables.

Polychotomous keys are used in troubleshooting to build troubleshooting charts and in classification/identification schemes with characteristics that have more than one attribute and the order of characteristics is not inherently based on the progression of time.

Decision points or independent variables with two states have a binary root that is referred to as a dichotomous key whereas the term polychotomous key refers to roots which are greater than one or unitary and usually greater than two or binary.