In the July 12, 2009 New York Times Magazine, contributing writer Lisa Belkin bemoans that there is no word for a woman who has been cuckolded,
I can find nothing in the dictionary that applies to sexually betrayed women, though you would think Webster would have added one by now).
It is true that neither Merriam-Webster's Collegiate Dictionary nor the American Heritage Dictionary has such a word, the word does exist and it is included in numerous dictionaries, both in print and online. Had Ms. Belkin looked at a dictionary other than the one sitting on her desk, she would have found cuckquean, a coinage dating back to the 16th century. It's relatively uncommon, which is probably why Merriam-Webster's Collegiate and American Heritage didn't devote space to it, but it can be found in the Oxford English Dictionary, the Shorter Oxford English Dictionary, and Merriam-Webster's Third, among others. Collegiate dictionaries, limited to a single, easily handled volume, are very space constrained and typically only include very common words.
In addition to her lack of research skills, this statement by Ms. Belkin demonstrates three common misconceptions about language and dictionaries. The first is that there is "the" dictionary, a sole, omniscient source of authoritative knowledge about our language. The second is that dictionary editors decide which words we should use. And the third is that the word Webster's has some meaningful significance.
There is no such thing as "the" dictionary. There are variety of dictionaries, often created with different purposes in mind. Some, like Merriam-Webster's Collegiate, are designed as desktop, quick-reference volumes. They include only words that readers and writers are likely to come across in daily use. Since they have to be contained within a single, easily handled volume, collegiate dictionaries do not attempt to be comprehensive record of the English language. Historical dictionaries like the OED, are comprehensive, but even they aren't complete. An online source has no space constraints, but there are limits on editorial time. So even big, unabridged dictionaries will omit occasional and nonce words, words that might be included in a slang dictionary. Other dictionaries limit themselves to a narrow field. So back in 1961 the editors at Merriam-Webster concluded that cuckquean merited inclusion in their Third New International dictionary. But forty-two years later in 2003, they decided that it didn't merit inclusion in their 11th Collegiate edition; different standards for different dictionaries. Which dictionary you consult depends on what you are trying to do. You can't draw a conclusion about a word's existence by looking at a collegiate dictionary.
Lexicographers are descriptivists, not prescriptivists. The dictionary doesn't tell us what words we should use; it tells us what words we do use. Just because a dictionary editor thinks there should be word for a female cuckold, doesn't mean she is going to add one to the dictionary just because it "should" be there. The word has to actually exist and be used to some degree first. Whether or not that usage merits inclusion in the dictionary, depends on the particular editorial guidelines the dictionary uses.
Finally, the descriptor Webster's is meaningless. When you refer to Webster's, all you are doing is displaying your ignorance of dictionaries. The term Webster's is not trademarked and is used by any number of publishers. Some, like Merriam-Webster, produce excellent products. Others are worse than useless. If you refer to a dictionary, refer to a specific one.
Also, a word of caution about referring to the Oxford English Dictionary, or OED. Properly speaking, the OED refers to the comprehensive, multi-volume reference produced by Oxford University Press. (The 1989 second edition has 20 volumes. The third edition, a work in progress, is only available online.) But Oxford University Press, like Merriam-Webster, produces a number of other dictionaries. There is the Shorter OED, the Oxford Dictionary of English, and the New Oxford American Dictionary, among others. Further confusing things, there are also two Compact OEDs; one is a single-volume, small-print version of the OED second edition, magnifying glass included, and the second is a collegiate dictionary. When referring to a dictionary by Oxford University Press, be specific and don't just call them the OED, unless you are referring to the big one.