A rendezvous or meeting (an arranged place or appointment to meet someone).
駅の出口で彼と待ち合いをした。
I met him at the station exit.
二人は秘密の待ち合いを公園で約束した。
The two arranged a secret rendezvous in the park.
待合の時間に遅れると連絡してください。
Please contact me if you're going to be late for the meeting time.
The area where guests wait before entering the main tea-room in a tea ceremony.
茶会の当日、客はまず待合で控え、亭主の合図を待つ。
On the day of the tea gathering, guests first wait in the machiai and await the host's signal.
待合には季節の花が一輪、生けられていた。
A seasonal flower was arranged in the machiai.
An abbreviation of 'waiting room' — a place where people wait (e.g., at a hospital or office).
病院の待合で雑誌を読んで時間をつぶした。
I killed time reading magazines in the hospital waiting area.
待合は混んでいるので、外でお待ちください。
The waiting area is crowded, so please wait outside.
名前が呼ばれるまで待合でお待ちください。
Please wait in the waiting area until your name is called.
An archaic sense: a meeting place for assignations or drinking (historically like a teahouse used for meetings).
江戸時代には町に待合があり、芸者と客がそこで会った。
In the Edo period there were machiai in towns where geisha and clients met.