Merriam-Webster Pocket Dictionary

Merriam-Webster Pocket Dictionary is a well-known software dictionary that provides high translation rate, easy-to-use interface, detailed, and up-to-date dictionary bases with numerous sound samples.
It comes with lots of nice features and tools at hand, together with a lightweight and clean layout.

Sleek graphical interface with many tools

The application doesn't take long to install and it doesn't come with a complicated setup that you would need to complete before you can actually use it. It sports a really intuitive graphical interface with plenty of tools and sections.
Merriam-Webster Pocket Dictionary is a dictionary that contains 40,000 definitions and lots of more features that you can check out.

Translate words and phrases

Words and phrases are searched for in Merriam-Webster within the active translation direction (a group of dictionaries representing one language pair). You have the option to check the dictionary and view explanations for all sort of words in the dictionary.
You can also use the search bar in order to find certain words. It comes with text-to-speech features, it pronounces words so you would know how they sound.

Create your own dictionary

The application comes with the option to create your own dictionary, select a name, the source language, the destination language and your name as the author.
You can also import certain dictionaries from your computer. Dictionaries are saved on your system, but you will need to create individual entries for them.

More features and tools

You can listen to most of the words in Merriam-Webster and view the grammar forms of a word. General Merriam-Webster settings configure the application behavior towards the user's actions (creation of user bookmarks, window minimization to the taskbar, exit from the application, etc.).
The interface settings window allows defining fonts (of interface and dictionary entries) and the language. All in all, Merriam-Webster Pocket Dictionary is a very nice application that you could use in order to learn English, check grammar and definitions, together with pronunciation of various words.