risorius

Borrowed from Late Latin rīsōrius (“ridiculous, laughing”), clipping of mūsculus rīsōrius (“laughing muscle”).

• (Received Pronunciation) IPA^(key): /ɹɪˈsɔː.ɹi.əs/, /ɹɪˈzɔː.ɹi.əs/
• (General American) IPA^(key): /ɹɪˈsɔɹ.i.əs/, /ɹɪˈzɔɹ.i.əs/
• Rhymes: -ɔːɹiəs

risorius (plural risorii)

1. (anatomy) A narrow band of facial muscle arising from the fascia over the masseter and inserting into the tissues at the corner of the mouth, which it draws laterally, as is used when smiling.

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

From rīsor (“laugher, mocker”) +‎ -ius (adjectival suffix).

• (Classical Latin) IPA^(key): [riːˈsoː.ri.ʊs]
• (modern Italianate Ecclesiastical) IPA^(key): [riˈs̬ɔː.ri.us]

rīsōrius (feminine rīsōria, neuter rīsōrium); first/second-declension adjective (Late Latin)

1. ridiculous, laughing, smiling

First/second-declension adjective.

• → English: risorius