Dichotomous key

Definition

A tool that allows the identification of organisms through a series of choices that lead to the correct name of a given item. Each step in the key presents two choices, leading the user to the next pair of choices or to the identification.

Etymology

From Greek 'dichotomos', meaning 'divided in two parts', and 'key', referring to a tool for determining the identity of organisms.

Example

To identify the insect specimen, the entomologist used a dichotomous key to narrow down the possible species based on its physical characteristics.

Synonyms

• Identification key
• Diagnostic key

Related Terms

• Taxonomy
• Identification guide
• Classification

Usage Notes

Dichotomous keys are widely used in biology and can be used for identification in both field guides and laboratory settings. They may be presented in written form or as part of interactive digital tools.