How does this translate?
Please take a seat.
The primary meaning of 掛ける is “to hang something on” (e.g. hang a painting on a wall). However, 掛ける is also a shorten form of 腰を掛ける (こしをかける), literally meaning “to hang your hip/waist on something”. 腰を掛ける is a synonym of 座る (すわる) = to sit down.
- 椅子に腰を掛けてください = Please sit down on this chair.
Those mean exactly the same. And the first sentence sounds super wordy. So, just memorize the second one as a common set phrase. お掛けください is frequently used between hosts and guests.
Please note that 掛ける has a variety of meanings. お掛けください can also mean:
Please call this telephone number.
because 電話をかける means “to make a phone call”. For example,
If you need me, don’t hesitate to contact me at this number. = 遠慮なくこの電話番号までおかけください。
電話をかける can be written as 掛ける (to hang) or 架ける (to bridge) in Kanji. However, a professional proofreading team at Mainichi Newspaper (one of the big five national newspapers) recommends to write it in Hiragana. For more information about the difference, please read this article.
We usually write 掛ける in Kanji when it means “to sit down”, though.