Not sure which Fortran this refers to. I never used Fortran I, but as I understand it, names were up to 6 characters long, first character alphabetic; names with initial letter A-H and O-Z were REAL, I-M INTEGER (Fortran II added declarations to override the defaults). Dartmouth Basic restricted names to a single letter and an optional digit.
Incidentally, the various Autocode languages of the 1950s in Britain had 1-character variable names.
That’s super interesting. It would have been some mainframe fortran from the 1970s because I remember him bringing me and my brother as children into a university computer lab where he had weaseled some time on a mainframe so he could punch cards. He told me the variable naming thing (and was prone to exaggeration) so it might not even be true - I can’t ask him now as he’s writing pseudo fortran implementations of Newton-Raphson with short variable names in the great computer lab in the sky at the moment.
Incidentally, the various Autocode languages of the 1950s in Britain had 1-character variable names.