It’s not how you think it would be pronounced.
Not “see-dle” or “sai-leed” but actually “kay-lee.” A ceilidh is a traditional Scottish dance, it’s sort of like line dancing. This was the first ceilidh of the year and it was PACKED! People were lining up 30 minutes before and the queue to get in was all the way down three flights of stairs (even after the first half of the event).
Here’s a recap of my first ceilidh: