General English language dictionaries are extremely useful learning resources for students in all discipines. Besides helping students learn the definitions of unfamiliar words, they can help students expand their vocabulary, clarify word usage, and learn the history of words (or perhaps more importantly, they can make students aware that words can even have a history, one that is inextricably linked to the social, political, and economic changes of a culture).

Dictionaries have histories, too, often contentious, such as the controversy between prescriptivists and descriptivists in the early 1960s over the former’s perception of the excessive permissiveness of Webster’s Third New International Dictionary of the English Language (1961), a.k.a. W3. The subsequent publication of the American Heritage Dictionary (1969) was the prescriptivists' response to W3. A similar debate raged more recently in 1981 over the Random House Dictionary (2nd unabridged ed.), which many prescriptivists again complained was too permissive.

Presently, the “big four” dictionary publishers are Merriam-Webster, Webster’s New World Dictionaries, Random House, and Houghton Mifflin (which publishes the the American Heritage Dictionary).Most people mistakenly assume that the word “Webster” in the title means that a dictionary is good and that it derives from the famous lexicographer Noah Webster. In fact, the word “Webster” in the title of a dictionary doesn’t necessarily have anything to do with its quality or its affiliation with Noah Webster. Only dictionaries published by Merriam-Webster are affiliated with Noah Webster. Over the years, there has been quite a bit of controversy and some litigation over the use of the name “Webster” in dictionary titles.

Dictionaries should be evaluated in terms of content, quality, and price. Before purchasing a dictionary, students and teachers should consider the following:
whether the contents are current
thoroughness, accuracy, precision, objectivity
number and effectiveness of word histories
effectiveness illustrative quotation, examples, pictures or other graphics
number and extent of synonym and antonym listings and cross-references
variant spellings and pronunciations
precise yet usable pronunciation system
adequate usage information
type of English emphasized (British or American?)
special lexical features (e.g., dating the first use of a word, labeling figurative meanings, etc.
price compared to competition.

Based on the above criteria, some of the best English language dictionaries are listed in the linked table. Of the four dictionaries listed, Random House Webster’s has the fewest listings for archaic words that appear in classical works and probably is not the best dictionary for students studying literature, religion, or other related subjects.; Webster’s New World Dictionary of the American Language is far better. On the other hand, the American Heritage Dictionary and Merriam-Webster’s Collegiate Dictionary both have superior coverage of many scientific and technical words. Merriam Webster’s also includes for many entries the date of first use.

Given the potential learning value of dictionaries, why do students seem so unwilling to use them? Laziness may account for some student resistance, but ignorance may be a cause as well. Many students simply may not know how to use a dictionary effectively and are unaware of the vast amounts of information they contain.

But according to Eckstrom Library’s Assistant Head Reference Librarian, Mildred Franks, “Most students just aren’t curious about words. If students were to start reading a dictionary, read the definitions and look at the elements that were offered, then if they have any intellectual curiosity whatsoever, they are bound to be inspired.”

Teachers in all disciplines are in a position to encourage students to use dictionaries, and Franks notes several ways that teachers can do so:
Talk about words, particularly in the context of the subject matter of the class.
Have students look up the origin of slang or popular idioms.
Take a good desk dictionary to class each day.
Point out the help that is in the front matter of dictionaries, as well as the non-lexical [encyclopedic] information.
Make assignments that require students to look up words in 6 or 7 different dictionaries, perhaps from different historical periods, then have them compare and contrast the definitions.

Ultimately, to encourage students to become more conscientious and effective users of dictionaries, teachers themselves need to be aware of and able to use their various lexical and non-lexical features. So take another look at this wonderful resource, and see how you and your students might be able to use it!