Quarterly means happening four times a year, once every three months. Since a year has twelve months, dividing it into four equal parts gives you quarters of three months each: January through March, April through June, July through September, and October through December.

Many businesses publish quarterly reports to show how they're doing financially each quarter. Schools often send home quarterly progress reports between the longer report cards. Magazines that come out quarterly arrive four times a year instead of monthly or weekly.

You might hear adults say they have a quarterly meeting or pay taxes quarterly, meaning four times spread evenly across the year.

When something happens quarterly, it creates a rhythm to the year that's more frequent than annually (once a year) but less rushed than monthly. It gives people regular checkpoints to measure progress, review results, or plan ahead without having to do it all the time.