paedomorphosis
noun
pae·do·mor·pho·sis ˌpē-də-ˈmȯr-fə-səs 
: phylogenetic change that involves retention of juvenile characters by the adult
Word History
Etymology
New Latin, from paed- + Greek morphōsis formation, from morphoun to form, from morphē form
First Known Use
1922, in the meaning defined above
Medical Definition
paedomorphosis
noun
pae·do·mor·pho·sis
variants or pedomorphosis
-ˈmȯr-fə-səs
plural paedomorphoses -ˌsēz
: phylogenetic change that involves retention of juvenile characters by the adult