+.Ss Delimiters
+When a macro argument consists of one single input character
+considered as a delimiter, the argument gets special handling.
+This does not apply when delimiters appear in arguments containing
+more than one character.
+Consequently, to prevent special handling and just handle it
+like any other argument, a delimiter can be escaped by prepending
+a zero-width space
+.Pq Sq \e& .
+In text lines, delimiters never need escaping, but may be used
+as normal punctuation.
+.Pp
+For many macros, when the leading arguments are opening delimiters,
+these delimiters are put before the macro scope,
+and when the trailing arguments are closing delimiters,
+these delimiters are put after the macro scope.
+For example,
+.Pp
+.D1 Pf \. \&Aq "( [ word ] ) ."
+.Pp
+renders as:
+.Pp
+.D1 Aq ( [ word ] ) .
+.Pp
+Opening delimiters are:
+.Pp
+.Bl -tag -width Ds -offset indent -compact
+.It \&(
+left parenthesis
+.It \&[
+left bracket
+.El
+.Pp
+Closing delimiters are:
+.Pp
+.Bl -tag -width Ds -offset indent -compact
+.It \&.
+period
+.It \&,
+comma
+.It \&:
+colon
+.It \&;
+semicolon
+.It \&)
+right parenthesis
+.It \&]
+right bracket
+.It \&?
+question mark
+.It \&!
+exclamation mark
+.El
+.Pp
+Note that even a period preceded by a backslash
+.Pq Sq \e.\&
+gets this special handling; use
+.Sq \e&.
+to prevent that.
+.Pp
+Many in-line macros interrupt their scope when they encounter
+delimiters, and resume their scope when more arguments follow that
+are not delimiters.
+For example,
+.Pp
+.D1 Pf \. \&Fl "a ( b | c \e*(Ba d ) e"
+.Pp
+renders as:
+.Pp
+.D1 Fl a ( b | c \*(Ba d ) e
+.Pp
+This applies to both opening and closing delimiters,
+and also to the middle delimiter:
+.Pp
+.Bl -tag -width Ds -offset indent -compact
+.It \&|
+vertical bar
+.El
+.Pp
+As a special case, the predefined string \e*(Ba is handled and rendered
+in the same way as a plain
+.Sq \&|
+character.
+Using this predefined string is not recommended in new manuals.