Shareware definition is a device that can be obtained or distributed freely. Software that can be obtained free of charge, but you are only entitled to evaluate the software during the period of time (try before you buy). Once past the deadline, and if you are interested to continue using the program, you must pay into the program makers. Some shareware not be used after the deadline passed, there is also a downgrade to the program, and some are still used even past the time limit.
Shareware is not free software or even semi-free. This is because:
1) Most of the shareware, source code is not available, so you can not modify the program at all.
2) Shareware does not allow someone to make a copy and install it without paying licensing fees. But in practice, people often disregard the distribution terms and do this anyway.
Several types of shareware software licenses are:
1) Site Licences: Software that may be used in all computer locations.
2) Concurrent-use Licences: allow use a number of copies of software at the same time.
3) Multiple User Licences: determine how many people are allowed to use the software.
4) Single User Licences: limiting use of software is only for one person.
5) Public Domain Software: is software that is not protected by copyright and may be used by anyone