Entry 1 sense Webster, 1913 achondroplasia · IPA /eɪˌkɒndɹə(ʊ)ˈpleɪziə/ 01 n. A skeletal disorder beginning before birth; cartilage is converted to bone resulting in dwarfism. 1. A skeletal disorder beginning before birth; cartilage is converted to bone resulting in dwarfism.(Med.)