rictus

UK: /ˈrɪktəs/ US: (rik′təs)

WordReference Random House Unabridged Dictionary of American English © 2026

ric•tus  (rik′təs), n., pl. -tus, -tus•es. 

1. Birds the gape of the mouth of a bird.
2. Physiology the gaping or opening of the mouth.

• Latin: wide-open mouth, equivalent. to rig-, variant stem of ringī to open the mouth wide + -tus suffix of verb, verbal action.
• 1750–60

ric′tal, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

rictus / ˈrɪktəs/ noun ( -tus, -tuses)

1. the gap or cleft of an open mouth or beak
2. a fixed or unnatural grin or grimace, as in horror or death

Etymology: 18th Century: from Latin, from ringī to gape

ˈrictal adjective