plantigrade UK /ˈplæntɪɡɹeɪd/US /ˈplæntəˌɡɹeɪd/adjective 1noun 1forms 1 adjective1 •Of an animal: walking with the entire sole of the foot on the ground. noun1 •A plantigrade animal; an animal that walks with the entire sole of the foot on the ground. formsplantigrades