This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
晪 combines 日 (sun) with 典, but the historical origin and original meaning are uncertain. It may have been a phono-semantic compound, but the exact development is unclear.
The sun 日 beside 典 suggests brightness or clarity, but the exact meaning is not fixed. Imagine a bright sun illuminating a classic text (典), making everything clear.
For テン, picture the sun (日) shining on ten (テン) classic books (典): ten -> テン.