The Redwax Project defines a release to be the same as that published by The Apache Software Foundation, and the release process is broadly similar.
Generically, a release is anything that is published beyond the group that owns it. For a Redwax project, that means any publication outside the development community, defined as individuals actively participating in development or following the dev list.
More narrowly, an official Redwax release is one which has been endorsed as an "act of the Redwax Project" by the Committers of a Redwax project.