The Collaborative International Dictionary of English v.0.48:

Register \Reg"is*ter\ (r[e^]j"[i^]s*t[~e]r), v. t. [imp. & p. p.
   Registere (-t?rd); p. pr. & vb. n. Registering.] [Cf. F.
   regisrer, exregistrer, LL. registrare. See Register, n.]
   1. To enter in a register; to record formally and distinctly,
      as for future use or service.
      [1913 Webster]

   2. To enroll; to enter in a list.
      [1913 Webster]

            Such follow him as shall be registered. --Milton.
      [1913 Webster]

   3. (Securities) To enter the name of the owner of (a share of
      stock, a bond, or other security) in a register, or record
      book. A registered security is transferable only on the
      written assignment of the owner of record and on surrender
      of his bond, stock certificate, or the like.
      [Webster 1913 Suppl.]

   Registered letter, a letter, the address of which is, on
      payment of a special fee, registered in the post office
      and the transmission and delivery of which are attended to
      with particular care.
      [1913 Webster]