囸:
1. Same as "日" (rì) - sun.
"囸, 人质切. 日月也." (From "改併四聲篇海归部" referencing "奚韻": "囸, pronounced as 'ren zhi'. It refers to the sun and moon.")
"囸, 古文日字." (From "篇海類編•人事類•囗部": "囸 is the ancient form of the character for sun.")
It is also said to be the same as "實" (shí).
"囸, 楊時喬《古文周易》: 與實同." (From "字彙補•囗部": "'囸' is the same as '實', as mentioned in Yang Shiqiao's 'Ancient Texts of the I Ching'.")
2. (Noun) (Pictophonetic. The forms in oracle bone script and small seal script resemble the shape of the sun. The outline is circular, representing the sun, with one horizontal line or a dot indicating sunlight.
Primary Meaning: sun)
Same as the primary meaning, "日", which denotes the essence of the sun. From the component "囗" and one, suggesting a pictorial representation.
— "说文" (Shuō Wén)