ginglymus

noun
gin·​gly·​mus | \ -glə-məs How to pronounce ginglymus (audio) \
plural ginglymi\ -​ˌmī How to pronounce ginglymi (audio) , -​ˌmē How to pronounce ginglymi (audio) \

Medical Definition of ginglymus

: a joint (as between the humerus and ulna) allowing motion in one plane only