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

first generation language

   Raw machine code.  When computers were first "programmed"
   from an input device, rather than by being rewired, they were
   fed input in the form of numbers, which they then interpreted
   as commands.  This was really low level, and a program
   fragment might look like "010307 010307".  Almost no one
   programs in machine language anymore, because translators are
   nearly trivial to write.

   (1994-12-01)