dictionaries

** Monolingual dictionaries ** (English-English)

 * [|dictionary.com]
 * [|dictionary.cambridge.org]
 * [|merriam-webster.com]
 * [|thefreedictionary.com]
 * [|macmillandictionary.com]
 * [|dictionary.net]
 * [|websters-online-dictionary.org]

Bilingual dictionaries or translators (English-Spanish; Spanish-English)
media type="custom" key="7767021"
 * [|wordreference.com]
 * [|dictionary.com]
 * [|websters-online-dictionary.org]
 * [|spanishdict.com]

Thesaurus (synonyms and antonyms)

 * [|thesaurus.com]
 * [|merriam-webster.com]
 * [|thefreedictionary.com]
 * [|macmillandictionary.com]
 * [|websters-online-dictionary.org]

Spanish dictionaries

 * [|rae.es]
 * [|wordreference.com]
 * [|thefreedictionary.com]
 * [|clave.librosvivos.net]

In English

 * [|britannica.com]
 * [|reference.com]
 * [|thefreedictionary.com]
 * [|encyclopedia.com]
 * [|wikipedia.org]

In Spanish

 * [|kalipedia.com]
 * [|wikipedia.org]