GNU Wget is licensed under the GNU General Public License (GNU GPL), which makes it free software. Please note that “free” in “free software” refers to liberty, not price. As some people like to point out, it's the “free” of “free speech”, not the “free” of “free beer”.
The exact and legally binding distribution terms are spelled out below. The GPL guarantees that you have the right (freedom) to run and change GNU Wget and distribute it to others, and even—if you want—charge money for doing any of those things. With these rights comes the obligation to distribute the source code along with the software and to grant your recipients the same rights and impose the same restrictions.
This licensing model is also known as open source because it, among other things, makes sure that all recipients will receive the source code along with the program, and be able to improve it. The GNU project prefers the term “free software” for reasons outlined at http://www.gnu.org/philosophy/free-software-for-freedom.html.
The exact license terms are defined by this paragraph and the GNU General Public License it refers to:
GNU Wget is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.GNU Wget is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
A copy of the GNU General Public License is included as part of this manual; if you did not receive it, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
In addition to this, this manual is free in the same sense:
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with the Invariant Sections being “GNU General Public License” and “GNU Free Documentation License”, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License”.
The full texts of the GNU General Public License and of the GNU Free Documentation License are available below.