Commonly keeps out of sight for a day in Rome (4)

I believe the answer is:

ides

I'm a little stuck... Click here to teach me more about this clue!

'day in rome' is the definition.
(Roman calendar term, as in the Ides of March)

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for ides that I've seen before include "13th or 15th day of the month in Roman calendar" , "Julius Caesar was killed during the . . . . of March" , "(In March) Caesar's time to beware" , "For example, March 15 in the Roman calendar" , "Caesar was killed in this side of March" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.