Hi, well if you mean russian to english dictionary, i looooove "context.reverso.net" and also i have on my phone the russian-english oxford dictionary and i really like this one for the technical aspect, you have to buy it, but i like that it has the stressed letters marked in red, when you search for a verb it always gives you the perfective and imperfective form, and in general i think is quite handy :)

https://wooordhunt.ru
It has a lot of examples of using words in context. 

https://www.lingvolive.com website is a good helper.

I'm using ABBYY Lingvo dictionary, simple UI, easy to use, perfect for study Russian grammar.

I can recommendy you Wordreference English-Russian dictionary, I personally find it quite useful.