VERB (3)

1. provide additional insurance for;

2. insure again by transferring to another insurance company all or a part of a liability assumed;

3. insure again by assuming all or a part of the liability of an insurance company already covering a risk;

The Collaborative International Dictionary of English v.0.48:

Reinsure \Re`in*sure"\ (-sh?r"), v. t.
   1. To insure again after a former insurance has ceased; to
      renew insurance on.
      [1913 Webster]

   2. To insure, as life or property, in favor of one who has
      taken an insurance risk upon it.
      [1913 Webster]

            The insurer may cause the property insured to be
            reinsured by other persons.           --Walsh.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

re-insure \re-insure\ v.
   1. to provide additional insurance for.

   Syn: reinsure.
        [WordNet 1.5]

   2. to insure again by transferring to another insurance
      company all or a part of a liability assumed.

   Syn: reinsure.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

reinsure
    v 1: provide additional insurance for
    2: insure again by transferring to another insurance company all
       or a part of a liability assumed
    3: insure again by assuming all or a part of the liability of an
       insurance company already covering a risk