sternocleidomastoid UK /ˌstɜː.nə(ʊ)ˌklʌɪ.də(ʊ)ˈma.stɔɪd/US /ˌstɝ.nəˌklaɪ.dəˈmæˌstɔɪd/adjective 2noun 1forms 1 adjective2 •Relating to or involving the sternum, the clavicle and the mastoid process of the temporal bone. •Of or pertaining to the sternocleidomastoid muscle. noun1 •Ellipsis of sternocleidomastoid muscle. formssternocleidomastoids
