What does cron mean?
Cron is a time-based scheduling utility found on Unix and Unix-like operating systems, including Linux and macOS. Its name derives from the Greek word for time, chronos. As a continuously running background process, known as a daemon, cron reads configuration files called crontabs and executes commands or scripts automatically at specified times, dates, or intervals — hourly, daily, weekly, or on more complex schedules. Tasks run this way are commonly called cron jobs, and they handle much of the invisible maintenance work of modern computing: backups, log rotation, report generation, and system updates typically happen through cron while no one is watching. First written for early Unix systems in the 1970s, cron has remained essentially unchanged in concept for decades, making it one of the oldest and most durable tools in computing. For anyone who works with servers, understanding cron is a practical necessity rather than an optional curiosity.
nounA time-based scheduling program on Unix and Unix-like operating systems that automatically runs specified commands or scripts at fixed times, dates, or intervals; also, by extension, any such scheduled task.
- The Unix time-based job-scheduling daemon that executes commands at specified dates and times.
- A scheduled task or script executed by this scheduler (a 'cron job').
- Rarely, a reference to the Greek titan Chronos/Cronus as a personification of time.
"The nightly backup is handled by a cron job that runs at 2 a.m."
"Set up a cron job to clear the cache every Sunday night."
"The report failed to generate because the cron daemon wasn't running."
Rarely pluralized; when it occurs, it usually refers to multiple scheduled jobs or instances of the scheduler across different systems.
"We run separate crons on each server so a single failure doesn't stop the backups."
Named after the Greek god of time, Cronus, cron has been quietly waking up servers around the world every night since the 1970s — and most people never notice it working.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cron
The name cron comes from the Greek word chronos, meaning time, which also gives us words like chronology and synchronize. The utility was written by Ken Thompson and later refined by Brian Kernighan's Bell Labs colleagues in the mid-1970s for early versions of Unix. The related terms crontab (short for 'cron table') and 'cron job' followed naturally from the tool's naming convention.
Related word forms
How cron is actually used
Strictly a computing term, familiar mainly to developers and system administrators; it would sound out of place in general conversation. In casual usage among programmers, 'a cron' often refers loosely to any regularly scheduled background task, even outside Unix systems.
Easily confused with cron
Corn is a cereal grain such as wheat or maize, while cron (spelled with an r) is the Unix scheduling tool.
A crone is an old woman, especially a witch-like figure in folklore, whereas cron is purely a technical computing term.