The Collaborative International Dictionary of English v.0.48:

Booked \Booked\, a.
   1. Registered.
      [1913 Webster]

   2. On the way; destined. [Colloq.]
      [1913 Webster]

   3. reserved in advance; held for future use. See
      reserve[2].
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Book \Book\, v. t. [imp. & p. p. Booked (b[oo^]kt); p. pr. &
   vb. n. Booking.]
   1. To enter, write, or register in a book or list.
      [1913 Webster]

            Let it be booked with the rest of this day's deeds.
                                                  --Shak.
      [1913 Webster]

   2. To enter the name of (any one) in a book for the purpose
      of securing a passage, conveyance, or seat; to reserve[2];
      also, to make an arrangement for a reservation; as, to be
      booked for Southampton; to book a seat in a theater; to
      book a reservation at a restaurant.
      [1913 Webster +PJC]

   3. To mark out for; to destine or assign for; as, he is
      booked for the valedictory. [Colloq.]
      [1913 Webster]

            Here I am booked for three days more in Paris.
                                                  --Charles
                                                  Reade.
      [1913 Webster]

   4. to make an official record of a charge against (a suspect
      in a crime); -- performed by police.
      [PJC]

WordNet (r) 3.0 (2006):

booked
    adj 1: reserved in advance [syn: booked, engaged, set-
           aside(p)]

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "booked":
   billed, documented, down, enrolled, entered, filed, indexed,
   inscribed, legal, logged, minuted, of record, official, on file,
   on record, on the books, posted, recorded, registered, scheduled,
   slated, to come, written down