In the glossary for mathematical operators in Unicode1, the last one, u+22FF "⋿", is said to represent "Z Notation Bag Membership".
Looking up "z notation bag membership" gives me this info:
The symbol "Z Notation Bag Membership" is included in the "Relations" subblock of the "Mathematics Operators" block and was approved as part of Unicode version 3.2 in 2002.
but really all this seems to tell me is that ⋿ is a relation of some sort.
On the Wiktionary2 for Z Notation Bag Membership,
- (mathematics) A Z notation operator indicating special-defined operation.
although there doesn't seem to be any other info I can find on this, so my question is: Is there any definition of ⋿, or is this a mathematical operator that doesn't really have any meaning?