sternocleidomastoid

Borrowed from New Latin sternocleidomastoīdēs, from Latin sternum (“the breastbone”) +‎ Ancient Greek κλείς (kleís, “the collarbone”) +‎ Latin mastoīdēs (“like a breast”), equivalent to sterno- +‎ cleido- +‎ mastoid.

• (Received Pronunciation) IPA^(key): /ˌstɜː.nə(ʊ)ˌklʌɪ.də(ʊ)ˈma.stɔɪd/
• (General American) IPA^(key): /ˌstɝ.nəˌklaɪ.dəˈmæˌstɔɪd/
• Rhymes: -æstɔɪd

sternocleidomastoid (not comparable)

1. (anatomy) Relating to or involving the sternum, the clavicle and the mastoid process of the temporal bone.
2. (anatomy) Of or pertaining to the sternocleidomastoid muscle.

• sternocleidomastoid muscle

sternocleidomastoid (plural sternocleidomastoids)

1. (anatomy) Ellipsis of sternocleidomastoid muscle.

• “sternocleidomastoid”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.
• “sternocleidomastoid”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.