[davidfor]

Originally Posted by Percivale

Thank You for all valuable answers
To make things clear:
-It is possible to add new dictionaries.

Strictly, no. The firmware supports a list of dictionaries. You cannot add extra, but people here have worked out ways to replace a dictionary.

-BUT is it possible to set such a dictionary as a default one??

The dictionary chosen will depend on the the language set in the book. If none, it will use the interface language. But, you can change the dictionary for a book and it will be remembered whenever you read that book.

-it is not possible to check the meaning of a phrasal verb since the dictionary doesn’t recognize more than one word at a time? Correct?

You can look up multiple words, but it the dictionary has to contain them. I have no idea how many there are in the supplied dictionaries. In fact, the only one I know of is "Buffalo Soldier"*.

-If come across a word which is not a typical lexical item but rather some scientific, biological etc. term - is it possible to look it up in Wikipedia in Kobo?

You can do a Wikipedia or Google search of any selected text in a book.

Is Kindle PW much better as far as dictionary possibilities are concerned?

Everybody says the supplied dictionaries in a Kindle are better than the Kobo. I don't have a Kindle to compare. For English, Kobo uses a Merriam-Webster dictionary. I believe it is the smallest of their electronic dictionaries.

* And Bob Marley has taken up residence in my brain for the rest of the day.