If you like words even a little bit, you should take advantage of Anu Garg‘s wordsmith.org. It is an idiosyncratic exploration of how language works; his “word a day” e-mail is particularly fun.
The “word a day” theme this week is “words with unusual arrangements of letters.” The first word in this series was “verisimilitude,” which Garg notes has perfectly alternating consonants and vowels. (Not bad, Anu, but my son’s name is even better, as it has perfect consonant-vowel symmetry while using only a single vowel: Solomon. An even longer example is Tunku Varadarajan‘s last name.)
“Verisimilitude” was followed by “syzygy” (“one could hyperpolysyllabically contrive a longer word having four Ys, but syzygy nicely lines up three of them organically in just six letters,” Garg notes) and “yob” (the rare word created by spelling a different word backward).

(Hemera)
But today’s word is my favorite. It’s “kine.” Before you click this link, or look the word up elsewhere, try to guess what is unique about it. A slight hint: the answer is related to the topic of this post and, marginally, this one one too. The answer is below.
Give up?
Kine is, as Garg write, “perhaps the only word in English that has no letters in common with its singular form, cow. Other words that are pluralized using -n marker are children, brethren, and oxen.”
Curious to know if any of you language mavens out there know of another word that suits these criteria. Also curious to know if you’ve ever used the word “kine” in a sentence. Verlyn Klinkenborg has, of course.

So what do cows have to do with a kinescope? (noun: the US name for television tube)
I suspect kinescope is more to do with kinetic…i.e movement, but cat bother to look it up
Think about it: kine is to cow as swine is to sow.
Well-loved. Like or Dislike:
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Ah, but what is the singular form of cattle?
I’d wager that a significant proportion of people who have said this word out loud were playing Vampire: The Masquerade at the time.
What is the only plural word that is made singular by ADDING an S?
Princes -> Princess
Not the only word —
millionaires -> millionairess
etc.
Well played, both of you. When I was told the riddle, I was told princes/princess was the only one. I suppose any words with this structure will work, though.
Most verbs. (They run. He runs.)
http://en.wikipedia.org/wiki/Da_kine
Exactly what I thought of when I read the question.
Mahalo nui loa
If you count ‘y’ as a vowel, I’ll give you alternating vowels and consonants with seemingly unnecessary y’s.
dasypygal
@Mattieshoes you beat me to it:
Kine is a popular Pidgin (ok, creole) catch-all in Hawaii. See also “Da Kine”
http://en.wikipedia.org/wiki/Da_kine
http://www.facebook.com/onekineday
Kine is well known as the “plural” to “cow”, but like “bek” for book, I always assumed that it was extinct.