prógramma

Greek pro- meant before and gramma meant something written. Prógramma described a public notice written in advance: the schedule of events at a festival, a proclamation posted before a vote. The word moved into Latin as programma and into early modern English as programme, still meaning a printed schedule of events — a theatre programme, an academic programme of study.

The computing sense emerged in the 1940s. Ada Lovelace had described an 'algorithm' for Charles Babbage's Analytical Engine in 1843, but the word program in a computing context crystallized with the Manchester Mark 1 and ENIAC in 1948–1949. Tom Kilburn and Freddie Williams, writing about the Manchester Mark 1, used 'program' to describe the stored sequence of instructions the machine would execute.

American English dropped the final -me of programme. When IBM adopted 'program' for computing instructions in the 1950s and 1960s, the American spelling became global computing standard. Today 'programme' means a television or educational schedule; 'program' means a piece of software. The same Greek root split into two distinct English words along national lines.

Every program is still a pre-written notice of what is to come — a sequence of instructions prepared in advance for an executor (human or machine) to follow. The Greek metaphor of posting instructions on a public board has transferred perfectly to the instruction set of a computer.