Today, in some official document I received, an enumeration (of items to address) had each line prepended with ㈰, ㈪, ㈫ etc.
From context, it is reasonably easy to guess that this might be an equivalent to numbers (①, ② etc) or roman letters (a, b, c etc).
I am familiar with the use of half-width katakana (ｱ, ｴ, ｲ etc) for that purpose, but it is the first time I see days of the week used that way (and surprisingly, there seems to be a set of dedicated characters for it).
Is there a name for this type of enumeration prefix, or at least for the characters themselves?
Do they have any special meaning, beside that of a regular enumeration (first item, second item etc)?
Is it standard to start with ㈰ and go from there? Is there anything after (土)?