WordNet (r) 3.0 (2006):

single quote
    n 1: a single quotation mark

The Free On-line Dictionary of Computing (30 December 2018):

single quote
'
apostrophe

    "'" ASCII character 39.

   Common names include single quote; quote; ITU-T: apostrophe.
   Rare: prime; glitch; tick; irk; pop; INTERCAL: spark;
   ITU-T: closing single quotation mark; ITU-T: acute accent.

   Single quote is used in C and derived languages to introduce
   a single character literal value which is represented
   internally by its ASCII code.  In the Unix shells and
   Perl single quote is used to delimit strings in which
   variable substitution is not performed (in contrast to
   double-quote-delimited strings).

   Single quote is often used in text for both open and close
   single quotation mark and apostrophe.  Typesetters use two
   different symbols - open has a tail going up, close and
   apostrophe have tails hanging down (like a raised comma).
   Some people use back quote (`) for open single quotation
   mark.

   (1998-04-04)