book in
US /bʊk ɪn/
UK /bʊk ɪn/

1.
reservar, fazer check-in
to arrange for someone to stay at a hotel, or for a seat on a plane, etc.
:
•
I'll book in for two nights at the hotel.
Vou reservar para duas noites no hotel.
•
Please book in your flight as soon as possible.
Por favor, reserve seu voo o mais rápido possível.
2.
registrar, marcar
to officially record someone's name as a visitor or for an appointment
:
•
The receptionist will book you in when you arrive.
A recepcionista vai registrá-lo quando você chegar.
•
Make sure to book in with the doctor's office for your annual check-up.
Certifique-se de marcar uma consulta no consultório médico para seu check-up anual.