What is the difference between a version, a variant, and a form of a folk song?

In the technical study of folklore, the terms version, variant, and form are used to categorize the relationships between different performances of a folk song. These distinctions help scholars map how songs evolve through oral transmission:1

• Version: This refers to a set of performances that are highly similar to one another, typically originating from a single singer.1
• Variant: This encompasses a collection of versions that are clearly related but exhibit more significant differences from one another than those found within a single version.1
• Form: This designates a broader body of performances that are related but not homogeneous. It represents a higher level of grouping for these related variants.1

Beyond these hierarchical classifications, the term "form" is also used in a musical sense to describe the internal structural interrelationship of a song's lines (such as ABCD or AABA). Because folk music is transmitted orally, it rarely exists in a single standard form, leading to the constant development of these unique versions and variants as songs cross regional, cultural, or ethnic boundaries.21