索 is a Japanese kanji written with 10 strokes, listed here under the keyword “cord”. It is built from 糸 (thread), 十 (ten) and 冖 (cover). In Remembering the Kanji by James W. Heisig it is frame 1465.
On KumiJi Glyph Explorer, open the parts search and type “thread” + “ten” + “cover”. 索 is among the results, together with every other character containing the same shapes.
Open 索 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.