sound hole
LEXIS
An acoustic ukulele has one or more round (or sometimes f-shaped) openings on its top where the sound is supposed to leave the body. Thus, a sound hole serves to amplify the sounds created by playing the instrument. It is protected by the rosetta.
Musubi
In most cases, sound holes are round. KoAloha however uses oval sound holes which are called musubi after the shape of Japanese rice balls.