Can I Build My Own Dictionary Application Using Online Data?

Because I'm a non-native English person, i use a lot a dictionary. Now I'm learning C# and i was thinking to if I'm allowed to build an application which will run on my machine, b

Solution 1:

Yes, and actually Google Translate has an API for you to do this: http://code.google.com/apis/ajaxlanguage/documentation/#fonje

Solution 2:

The Wikimedia foundation has database dumps from their projects online. You can download the Wiktionary dictionaries from http://download.wikimedia.org. Of particular use would be the one for a language you know well, so you can translate words in any language to your own.

For example, if your native language is Esperanto then you would download "eowiktionary" from http://download.wikimedia.org/backup-index.html

If you're learning C# this might be an interesting and useful project for you. And the Wikimedia data is certainly free for you to download use in this way. All Wikimedia content is licensed under the GNU Free Documentation License.

Solution 3:

It may be worth considering a desktop Gadget which does a similar thing.

Vista has sidebar gadgets which will do this, OS X has dashboard widgets which will do this, and Google Desktop has gadgets which will do this.

Solution 4:

There are literally thousands of dictionary software which you can download or buy. I even have one on my phone. Its perfectly legal to create your own if you want to. However, unless you come up with some new invention to the existing plethora of software, it might be hard to find people willing to use it.