How does a word become a word and get entered in the dictionary?

This is one of the questions Merriam-Webster editors are most often asked.

The answer is simple: usage.

Tracking word usage
To decide which words to include in the dictionary and to determine what they mean, Merriam-Webster editors study the language as it's used. They carefully monitor which words people use most often and how they use them.

Each day most Merriam-Webster editors devote an hour or two to reading a cross section of published material, including books, newspapers, magazines, and electronic publications; in our office this activity is called "reading and marking." The editors scour the texts in search of new words, new usages of existing words, variant spellings, and inflected forms—in short, anything that might help in deciding if a word belongs in the dictionary, understanding what it means, and determining typical usage. Any word of interest is marked, along with surrounding context that offers insight into its form and use.

Citations
The marked passages are then input into a computer system and stored both in machine-readable form and on 3" x 5" slips of paper to create citations.

Each citation has the following elements:

the word itself
an example of the word used in context
bibliographic information about the source from which the word and example were taken
Merriam-Webster's citation files, which were begun in the 1880s, now contain 15.7 million examples of words used in context and cover all aspects of the English vocabulary. Citations are also available to editors in a searchable text database (linguists call it a corpus) that includes more than 70 million words drawn from a great variety of sources.

From citation to entry
How does a word make the jump from the citation file to the dictionary?

The process begins with dictionary editors reviewing groups of citations. Definers start by looking at citations covering a relatively small segment of the alphabet — for example gri- to gro- — along with the entries from the dictionary being reedited that are included within that alphabetical section. It is the definer's job to determine which existing entries can remain essentially unchanged, which entries need to be revised, which entries can be dropped, and which new entries should be added. In each case, the definer decides on the best course of action by reading through the citations and using the evidence in them to adjust entries or create new ones.

Before a new word can be added to the dictionary, it must have enough citations to show that it is widely used. But having a lot of citations is not enough; in fact, a large number of citations might even make a word more difficult to define, because many citations show too little about the meaning of a word to be helpful. A word may be rejected for entry into a general dictionary if all of its citations come from a single source or if they are all from highly specialized publications that reflect the jargon of experts within a single field.

To be included in a Merriam-Webster dictionary, a word must be used in a substantial number of citations that come from a wide range of publications over a considerable period of time. Specifically, the word must have enough citations to allow accurate judgments about its establishment, currency, and meaning.

The number and range of citations needed to add a word to the dictionary varies. In rare cases, a word jumps onto the scene and is both instantly prevalent and likely to last, as was the case in the 1980s with AIDS. In such a situation, the editors determine that the word has become firmly established in a relatively short time and should be entered in the dictionary, even though its citations may not span the wide range of years exhibited by other words.

Size does matter
The size and type of dictionary also affects how many citations a word needs to gain admission. Because an abridged dictionary, such as Merriam-Webster's Collegiate® Dictionary, has fairly limited space, only the most commonly used words can be entered; to get into that type of dictionary, a word must be supported by a significant number of citations. But a large unabridged dictionary, such as Webster's Third New International Dictionary, has room for many more words, so terms with fewer citations can still be included.


Reference Link:

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