Cron is usually associated with cron job or cron table (crontab). So what is cron anyway? Basically cron is a task scheduler in Unix based environment operating systems. Cron enables user to schedule or run jobs ( jobs can be scripts or commands) to run at certain dates and times. Although commonly used for automating system maintenance or administration, it also can be used for other purposes depending on your creativity.
One fun fact, cron actually came from the word "chronos". It's actually Greek term for time.