See also: Non-Free
"Commercial", as opposed to "residential" or "private", describes a business and generally for-profit-driven activity.
In relation to software, the term "commercial" is often mis-used to refer to proprietary software or closed-source software. In reality, Free Software can also be commercial because everyone is permitted to sell it, and proprietary software can be distributed at no-cost, so it can be non-commercial. This confusion is a simple function of the ambiguity of the english language word "free".