back quote
"`" {ASCII} code 96. Common names: left quote;
left single quote; open quote; {ITU-T}: grave accent; grave.
Rare: backprime; {INTERCAL}: backspark; unapostrophe; birk;
blugle; back tick; back glitch; push; {ITU-T}: opening single
quotation mark; quasiquote.
Back quote is used in {Unix} shells to invoke {command
substitution}.
(1996-11-26)