codepoint - Why is 'U+' used to designate a Unicode code point?

Question

Why do Unicode code points appear as U+<codepoint>?

For example, U+2202 represents the character ?.

Why not U- (dash or hyphen character) or anything else?

Answer 1

The characters “U+” are an ASCIIfied version of the MULTISET UNION “?” U+228E character (the U-like union symbol with a plus sign inside it), which was meant to symbolize Unicode as the union of character sets. See Kenneth Whistler’s explanation in the Unicode mailing list.