B1
to arrange to use or do something at a particular time in the future
Dictionary examples:
I booked a karaoke night for the office, but everyone called in sick. (0.0)
I booked a clown for my boss's birthday. He hates surprises! (0.0)
Tom booked a skydiving lesson but forgot he was afraid of heights. (0.0)
Book early/in advance to get a good room. (28.5)
The hotel is booked solid / fully booked for the next three weeks. (35.0)
You need to book your flight before the fares go up. (35.0)