When you want to translate a word or phrase quickly, you can rely on these websites, which also have apps.
Google Translate https://translate.google.com – Quick and easy, it also has an audio icon to hear pronunciation. You can put in entire sentences or paragraphs, but be careful—the translations may need revision. If you put in a search for Google Translate online, a box will come up for translation without having to go to the website.
SpanishDict www.spanishdict.com – Good for quick translation, occasionally gives examples of of how the words are used; it also features oral pronunciation and entire verb conjugations if the word you looked up is a verb. You can put in entire sentences or paragraphs, but be careful—the translations may need revision.
Word Reference http://www.wordreference.com – Good for quick translation of individual words—will not do sentences. Gives examples of how the words are used and idiomatic expressions with the word. For intermediate and advanced students there are also interesting forums to learn the nuances of words or the differences in word usage between Spanish-speaking countries.