What is a “package”?
A package is anything you install using your package manager.
A "conda package" is a compressed tarball that contains
the module to be installed
information on how to install the package
You can use conda-build to build a conda package.
What about channels?
Channels contain packages.
They conform to a standard structure and contain an index of available packages.
An index of the available packages can be generated by running:
$ conda index <path to channel>
conda is able to install from channels and uses the indexes in the channel to solve for requirements and dependencies.