1.VerbTo retroactively supply to a previous version of a software product a fix or a new feature at the same time or after supplying it to the current version.
2.VerbTo re-release software on its original or a previous platform with new features, after its release on a different platform.
3.NounAn act of backporting.
"This backport fixes an urgent bug."
4.NounA software program that has been backported.