Freeware is software that is available for use at no monetary cost or for an optional fee (Wikipedia, "Freeware").
Freeware is computer software that is made available free of charge, but which is copyrighted by its developer, who retains the rights to control its distribution, modify it and sell it in the future. It is typically distributed without its source code, thus preventing modification by its users (Linfo, "Freeware Definition").
Like shareware, freeware is software you can download, pass around, and distribute without any initial payment. However, the great part about freeware is that you never have to pay for it. No 30 day limit, no demo versions, no disabled features -- it's totally free (Techterms.com, "Freeware").
Open source software allows access to the source code. Additionally, open-source software must adhere to the following criteria to be considered open source:
The following articles tell more about freeware and open source and how they are used.