The readings for this word are both kun'yomi readings, but it's like the hiragana that normally sticks out is stuffed in. 待ち → 待, 合い → 合 and is pronounced the same too. I know it's confusing, but once you get it down you'll never forget!
Start squatting in the meeting place on my signal.
The waiting room was so cold that I got a bladder infection.
I ran into a friend from a long time ago in the waiting room of the hospital and we chatted about the old days.