What ⑽ means
It marks item ten in a numbered list. Many enclosed-number symbols were designed as compact list bullets in legacy East Asian character sets. Parenthesized forms followed a typewriter convention, standing in for circled numbers used as list bullets. The parenthesized ten is one form in that family.
⑴ begins the same parenthesized-number series and marks item one. The exact first appearance of ⑽ is not dated in the supplied historical account.
Why does ⑽ look different in fonts?
Font design and text processing can change its appearance. Fonts draw the parentheses and spacing differently. Some text processing expands this one character into the three ordinary characters (10), so the enclosed shape is not preserved.
A compact, typographic marker that looks more formal than plain (10).
Use plain (10) if the parentheses must stay visible across text processing.
Don't confuse it with
3Questions people ask
1Why does ⑽ 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 ⑽
⑽\247DCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.

