Joseph Emerson Worcester (1784 - 1865) was an American lexicographer and chief competitor of Webster's Dictionary in the mid-nineteenth-century.

Worcester was born August 24, 1784, in Bedford, New Hampshire, and worked on a farm in his youth, entering school at fourteen. In 1809, he entered Yale and graduated in two years. He then taught school in Massachusetts for several years, during which time he produced several works on geography, including A Geographical Dictionary, or Universal Gazetteer, Ancient and Modern in 1817. He wrote a much used textbook, Elements of History, Ancient and Modern, accompanied by an Historical Atlas, published in 1827.

His first edited dictionary was an abridgment of Samuel Johnson's Dictionary of the English Language, published in 1828, the same year Noah Webster's American Dictionary appeared. Having worked as an assistant on the production of Webster's dictionary, he produced an abridgment of Webster's work in 1829. But, unlike Webster, used London for his guide to pronunciation and opposed Webster's spelling reforms (e.g. tuf for tough, dawter for daughter), to Webster's disaproval.

He published his own Comprehensive Pronouncing and Explanatory English Dictionary in 1830, inciting charges of plagiarism from Webster, to which Worcester protested that he had worked on his dictionary before working for Webster and had used his own research. In what is often referred to as the dictionary wars , rivalry and contention between the two men continued until Webster's death in 1843, and long after with Webster's successor, the G. & C. Merriam Company, which bought rights to the American Dictionary.

Worcester collected plilological works and wrote a journal in Europe in 1831, and then for many years co-edited the annual American Almanac and Repository of Useful Knowledge. In 1841 he married Amy Elizabeth McKean, but produced no children. He continued to revise his dictionary, producing A Universal and Critical Dictionary in 1846. When a British edition of the work stated that it was based on the work of Noah Webster, and omitted Worcester's introductory statement claiming otherwise, he responded with A Gross Literary Fraud Exposed. He earned LL. D degrees from Brown (1847) and Dartmouth (1856).

His culminating work, A Dictionary of the English Language, published in 1860 was briefly the major American dictionary, until Merriam's new edition of Webster's American Dictionary appeared in 1864. Worcester's work was the first American dictionary to incorporate illustrations throughout the text, and to offer treatment of synonyms, a feature of most major dictionaries since. It was posthumously revised in 1886, but was eclipsed by Webster's International and other dictionaries of the 1890s and went out of print before the turn of the century.

Worcester died October 27, 1865.

Worcester's works include:

A Geographical Dictionary, or Universal Gazetteer, Ancient and Modern (1817, enlarged 1823)

A Gazetteer of the United States (1818)

Elements of Geography, Ancient and Modern (1819)

Sketches of the Earth and its Inhabitants (1823)

Elements of History, Ancient and Modern, accompanied by an Historical Atlas (1826)

Epitome of History (reissue of above, 1827)

Outlines of Scripture Geography (1828)

Johnson's Dictionary, as improved by Todd and abridged by Chalmers, with Walker's Pronouncing Dictionary combined, to which is added Walker's Key (1828)

A Comprehensive Pronouncing and Explanatory Dictionary of the English Language with Pronouncing Vocabularies (1830)

A Universal and Critical Dictionary of the English Language (1846)

A Gross Literary Fraud exposed; relating to the Publication of Worcester's Dictionary in London: Together with Three Appendixes; Including the Answer of S. Converse to an Attack on him by Messrs. G. & C. Merriam (1854)

A Dictionary of the English Language (1860)

An Elementary Dictionary for the Common Schools with Pronouncing Vovabularies of Classical Scripture and Modern Geographical Names

An Elementary Dictionary of the English Language

A Primary Dictionary of the English Language