曜 is a Japanese kanji written with 18 strokes, listed here under the keyword “weekday”. It is built from 日 (day) and 翟 (futon). In Remembering the Kanji by James W. Heisig it is frame 618.
On KumiJi Glyph Explorer, open the parts search and type “day” + “futon”. 曜 is among the results, together with every other character containing the same shapes.
Open 曜 in the interactive kanji search
to expand every part down to its smallest pieces, add your own names and mnemonic stories,
or search for other characters by their parts.