What ⼂ means
Radical 3 is a dot-shaped dictionary heading.
丶 appears in writing on bronze around 1000 BC. The Chinese dictionary Shuowen, from around 100 CE, describes it as an ending mark and used 540 headings; ⼂ is the later radical form.
Radical indexes sort by component, then leftover strokes. The dictionary Zihui introduced a reduced radical list in 1615; the Kangxi Dictionary adopted it in 1716. Unicode’s ordering of Han characters draws on Chinese, Japanese and Korean dictionaries. A proposal for indexing simplified Chinese characters used 201 components in 1983.
Don't confuse it with
1Questions people ask
1Why does ⼂ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type ⼂
⼂\2F02Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.