The software world
Process
running program
A live, running copy of a program. The program is the file sitting on your disk; the process is what exists in memory while it's actually working. One program file can have many processes running from it at once — two browser windows are one program, two processes.
Why it matters
Part of Files, folders and paths → It's the distinction that explains a surprising amount: why closing a window doesn't always quit the app, why your machine slows down when you "only have one thing open", and why a server has to be running for a site to load. In Claude Code, "start the dev server" means launch a process and leave it running — a thing that exists until something stops it.
see also