//

The two /|slashes // may indicate:
 * a comment marker in several programming languages including C, C++, JavaScript and Java
 * the root directory path in Domain/OS
 * the operator for integer division, in Python 2.2+ and other programming languages
 * the empty pattern in Perl, which evaluates the last successfully matched regular expression
 * the logical defined-or operator in Perl, called the null coalescing operator in other programming languages
 * the authority indicator in the URI scheme, which follows a colon (://) from the scheme component
 * the descendant-or-self axis specifier in XPath
 * a double vertical bar (||) where the vertical line character &#124; is unavailable for technical reasons
 * the parallel operator stylized in pseudo-italics
 * a caesura in musical notation
 * a diaphoneme in linguistic transcription