Lexicography is an important branch of linguistics, which covers the theory and practice of compiling dictionaries. The history of lexicography of the English language goes as far back as the Old English period where its first traces are found in the form of the glosses of religious books with interlinear translation from Latin. Regular bilingual English-Latin dictionaries already existed in the 15th century.

The first unilingual English dictionary, explaining words appeared in 1604. Its aim was to explain difficult words. Its title was "A Table Alphabetical, containing and teaching true writing and understanding of hard usual English words borrowed from the Hebrew, Greek, Latin or French". The volume of 120 pages explaining about 3000 words was compiled by Robert Cawdrey, a schoolmaster.

The first attempt at a bigger dictionary including all the words of the language, not only the difficult ones, was made by Nathaniel Bailey. He published the first edition of Universal Etymological English Dictionary in 1721. It was the first to include pronunciation and etymology.

The first big explanatory dictionary "A dictionary of the English language in which the words are deduced from their originals and illustrated in their general significations by examples from the best writers" was compiled by Dr. Samuel Johnson and published in 1755. The most important innovation of this dictionary was the introduction of illustrations of the meanings of the words by examples from the best writers. Pronunciation was not marked, because Samuel Johnson was very much sure of the great variety of the English pronunciation and thought it impossible to set a standard there. He remained an unquestionable authority for more than 75 years.

The Golden Age of lexicography started in the last quarter of the 19 century when the English Philological Society started to work on compiling The Oxford English Dictionary. The objective was to trace the development of the English words from their original form in Old English. Where they were not found in Old English, it was shown when they introduced into the language. For words and meanings which have already become obsolete the date of the latest occurrence is provided. The English of G. Chaucer, of the Bible and W. Shakespeare is given as much attention as that of the modern authors. The completion of the work required more than 75 years. The result is a kind of encyclopedia of the language used not only for reference but also as a basis for lexicological research.

Curiously enough, the first American dictionary of the English language was compiled by a man whose name was also Samuel Johnson. Samuel Johnson, a Connecticut schoolmaster, published in 1798 a small book entitled "A school dictionary." This book was followed in 1800 by another dictionary by the same author, which showed already some signs of Americanization.

It was Noah Webster, universally considered to be the father of American lexicography, who embodied in his book the specifically American usage of his time. His great work, The American Dictionary of the English Language, appeared in two volumes in 1828 and later sustained numerous revisions. In many respect N. Webster follows the lead of S. Johnson, the British lexicographer. But he has also improved and corrected many of Johnson's definitions. He attempted to simplify the spelling and pronunciation that were current in the USA of the period. He devoted many years to the collection of words and the preparation of the accurate definitions.

Webster realized the importance of language for the development of a nation, and he devoted his energy to giving the American English the status of an independent language, distinct from British English. At that time the idea was progressive as it helped the unification of separate states into one nation.

Webster's dictionary enjoyed great popularity from its first editions. This popularity was due to not only the accuracy and clarity of definitions but also to the richness of additional information of encyclopedic character, which had become a tradition in American lexicography.

Soon after Webster's death two publishers and booksellers George and Charles Merriam, acquired the rights of his dictionary from his family and started the publication of revised single volume editions under the name Merriam-Webster.