Artefact Dictionary 

Artefact Dictionary integrates into the system and allows you to get an translation of any word or expression, regardless of which application displayed it. All you need to do - is to hold 'Alt' (or some other) key and select some text by the mouse.
dictionary translation explanatory explanation

McGill English Dictionary of Rhyme 

Free software rhyming dictionary derived from the award-winning McGill English Dictionary of Rhyme, which is used by tens-of-thousands of writers, educators, students, aspiring poets and songwriters from over 100 countries.
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