1A loanword meaning 'boy'. In practice, however, natives rarely use ボーイ this way in everyday speech — 男の子 or 少年 is used instead. It mainly survives in compounds or set phrases (e.g. オールドボーイ 'old boy').
2A bellboy, porter, or waiter — a male attendant who carries luggage or takes orders at a hotel, restaurant, or café. Also addressed as 'ボーイさん'.
ホテルのボーイが部屋まで荷物を運んでくれた。
The hotel's bellboy carried our luggage up to the room.
喫茶店のボーイに注文を頼んだ。
I gave my order to the waiter at the café.
昔は百貨店にもボーイと呼ばれる案内係がいた。
In the past, department stores also had attendants known as 'boys'.