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

left brace
open brace


    "{".  {ASCII character 123.

   Common names: open brace; left brace; left squiggly; left
   squiggly bracket/brace; left curly bracket/brace; ITU-T:
   opening brace.  Rare: brace ("}" = unbrace); curly ("}" =
   uncurly); leftit ("}" = rytit); left squirrelly; INTERCAL:
   embrace ("}" = bracelet).

   Paired with right brace ("}").

   (1995-03-16)