Apportionment Definition: The division and distribution of something into proportionate parts; to each according to their share. For example, if a court ordered apportionment of a contract, the party would be required to perform only to a extent equal to the performance of the other side. Find you are constantly looking up definitions? Try our search provider (works in most modern browsers) If you find an error or omission in Duhaime's Legal Dictionary, or if you have legal term suggestion, we'd love to hear from you!