For all the mentions of FORTRAN in the description of other languages, it's a real surprise that FORTRAN doesn't rate a mention of its own -- though there are corners of the world where it's still in use.

It's notable not only for being the Lingua Franca of scientific computing through at least the '80s, but also for breaking ground in programming language technology, starting right at the beginning -- the Fortran I compiler, for the IBM 704 in 1957, was the first to have an optimizer (and the technical papers on that compiler introduced terminology which has since become standard to the field -- e.g. "basic block").