IATE
IATE (Inter-Active Terminology for Europe) is the European Commission’s new multilingual terminological databank and replaces the earlier tool, Eurodicautom. This language site currently enables users to find translations for 1.4 million terms in 24 European languages, including Slovak and English.
http://iate.europa.eu/iatediff/SearchByQueryLoad.do?method=load

Slovnik
Instantly translate Slovak words into English with this free online multilingual dictionary.
http://slovnik.azet.sk/

NAPRI
This instant Slovak-English translator is a service of the Slovak Internet provider Napri.
http://www.napri.sk/

Dicts
On this Internet site, you can find a free online bilingual dictionary that allows you to translate Slovak words into English.
http://dicts.info/2/english-slovak.php

Freelang
On the Freelang site, you will find a free translation dictionary from Slovak to English, which you can consult online or download.
http://www.freelang.net/online/slovak.php

From Language to Language
From Language to Language is a language site offering a free translation dictionary from Slovakian to English. The multilingual Langtolang Dictionary enables users to translate words from and to 31 different languages.
http://www.langtolang.com/

Logos
Logos bills itself as the largest freely accessible multilingual dictionary on the web, with dictionaries in 232 languages. Slovakian words and phrases can be translated into English, and vice-versa, at the touch of a button. Logos also features a universal conjugator, children’s dictionary, and more than 43,000 online books in over 100 languages, including 18 in Slovakian.
http://www.logos.it/

Ectaco
This site offers instant translations of Slovak and English words. This free Slovak-English dictionary contains 400,000 words.
http://www.ectaco.co.uk/English-Slovak-Dictionary/

Monolingual Slovak Dictionary
Forma offers a free online monolingual Slovak dictionary, where you can find definitions of words in Slovak.
http://www.slex.sk/