Definition of symplesiomorphy in US English:

symplesiomorphy

noun

Taxonomy
  • The possession by two or more organisms or taxa of a shared primitive or ancestral character not exclusive to or characteristic of them in particular; the shared character itself.

Origin

1950s; earliest use found in Systematic Zoology. From sym- + plesio- + -morphy.

Pronunciation

symplesiomorphy

/sɪmˈpliːzɪə(ʊ)mɔːfi/