Difference Between Patch And Patchset

A patch is a one-off fix for a specific issue. The patch may be a manual process, or applied using the opatch utility. These changes may not result in an oracle version change, so it is only possible to tell that they have been applied by keeping a manual record, or by listing the patches applied via opatch, assuming that is how you applied them. Patches may have specific dependencies, so you must check you have the correct patch for your version.

A patchset is a collection or bundle of patches. Typically, a patchset is a more major operation, and as such will include be applied using the Oracle Universal Installer. The patchset will typically result in a significant version change, like 10.2.0.1.0 to 10.2.0.2.0 etc. Patchsets are usually cumulative, so you can patch anything from the base version release to the latest patchset in one go. So the same 9.2.0.8.0 patchset will be used to patch 9.2.0.1.0 and 9.2.0.7.0.

The word bundle implies a collection of patches, but a bundle may not be as big or important as a complete patchset. The bundle simply implies there are multiple patches bundles together.