? (thing) by ariels - Everything2.com

The question mark.
In chess, the symbol for a bad move.
"query" -- The accessor in BBC BASIC for a byte. ?1234 is the byte at address 1234 (decimal; in practice you'd want to use ?&4D2). In modern terminology, ?x was an lvalue; you could also assign to it.
Part of the ternary ("?:") operator in C (and its many offspring, including C++, Perl, csh, awk etc.).
In a regular expression, the customary symbol for an optional portion. In a UN*X shell like sh or csh, it is a wildcard (used for filename globbing), the symbol for any character.
In Nethack, a scroll.

?	!	?:	The world's shortest correspondence
Ternary	filename globbing	@	question mark
HTTP Headers	Unicode European Alphabets	blab!	BBC BASIC
lvalue	Nodespotting	META http-equiv	meta tag abuse
terminology	regexp	Byte	NetHack