Fortran (also FORTRAN) is a statically typed, compiled (sometimes interpreted), imperative, computer programming language originally developed in the 1950s and still heavily used for scientific computing and numerical computation half a century later.
The pioneers of FORTRAN didn't invent the idea of writing programs in a High Level Language (HLL) and compiling the source code to object code with an optimizing compiler, but they produced the first successful HLL.
They designed an HLL that is still widely used, and an optimizing compiler that produced very efficient code, in fact the FORTRAN I compiler held the record for optimizing code for 20 years!
This wonderful first FORTRAN compiler was designed and written from scratch in 1954-57 by an IBM team lead by John W. Backus and staffed with super-programmers like Sheldon F. Best, Harlan Herrick, Peter Sheridan, Roy Nutt, Robert Nelson, Irving Ziller, Richard Goldberg, Lois Haibt and David Sayre. By the way, Backus was also system co-designer of the computer that run the first compiler, the IBM 704.
The new invention caught quickly, no wonder, programs computing nuclear power reactor parameters took now hours instead of weeks to write, and required much less programming skill. Another great advantage of the new invention was that programs now became portable. Fortran won the battle against Assembly language, the first in a series of battles to come, and was adopted by the scientific and military communities and used extensively in the Space Program and military projects.