Dictionary.com

Multi-source dictionary service produced by Lexico Publishing Group, LLC, a leading provider of language reference products and services on the Internet.

Dictionary of Medical Acronyms & Abbreviations

4th Edition (2001)

Grove Art Online

The Grove Dictionary of Art Online provides Web access to the entire 34 volume text ofThe Dictionary of Art from 1996.

InfoPlease

The dictionary component of the Information Please bundle that includes an almanac, thesaurus, encyclopedia, and atlas.

Japan Knowledge

"The Japan Knowledge provides more than 30 databases such as 5 encyclopedias, 8 dictionaries, 7 full text magazines, interactive maps, video library, full text of the collection of Toyo Bunko, and more. It is the largest online reference resource on Japan."

KRpia

Full-text of various dictionaries and encyclopedias, classical and modern literature, primary sources, etc. in Korean language.

Merriam-Webster Online

This freely available (with advertising) version couples Merriam-Webster Online Dictionary and Thesaurus.

Na Puke Wehewehe Olelo Hawaii/Hawaiian Dictionary

Allows searches in Hawaiian or English.

New Grove Dictionary of Jazz

The New Grove Dictionary of Jazz, second edition, edited by Barry Kernfeld (London, 2002), ( 3 volumes) is part of Grove Music Online.

New Grove Dictionary of Music and Musicians

New Grove Dictionary of Music & Musicians is universally acknowledged as the unsurpassed authority on all aspects of music and is widely used throughout the academic and professional community. The online version contains the complete text of the print.

New Grove Dictionary of Opera

The New Grove Dictionary of Opera (4 volumes), edited by Stanley Sadie (London, 1992), is part of Grove Music Online.

Oxford English Dictionary (OED)

The Oxford English Dictionary is the preeminent historical dictionary of the English language. The OED Online contains the complete text of the 20-volume Second Edition, first published in 1989, together with its 3-volume Additions Series, published in 1993 (volumes 1 and 2) and 1997 (volume 3).

Reference.com

Includes a multi-source dictionary, thesaurus, almanac, atlas, etc.

Roget's Thesaurus

Search the headwords or full text of Roget's Thesaurus, 1911.

Stedman's Medical Dictionary

Part of eMedicine online.

Taber's Cyclopedic Medical Dictionary

20th Edition (2005)

World Almanac

via LexisNexis Academic