If, like me, you're long since tired of reading stories about Tiger Woods' sordid personal life, please hang with me for one more. It's an unusual story. I would expect nothing less from Slate. The online magazine is a great place to read unique angles to the same stories everyone else is reporting on. But this story may be an example of how sometimes Slate's need to be contrarian gets a little awkward. The headline gave the first hint:

Tiger Woods Does Not Have 11 "Mistresses"

What? He has more?!

Quite the contrary. In this article, Jesse Sheidlower, author of "The F-Word" and editor-at-large for the Oxford English Dictionary, argues that Woods has zero. He's not purporting that Woods wasn't a master of infidelity -- only that these liaisons don't rise to the level of respect reserved for the mistress to the marriage. This seems absurd to me, but in Sheidlower's opinion the mistress relationship has an element of sanctity that is higher than an open relationship but lower than marriage.

The word mistress entered English in the 14th century by way of French. Effectively equivalent to master with the ess feminine suffix, it originally meant "a woman having control or authority"—such as a woman who is the head of a household. By the 15th century, the word developed the meaning "a woman who is loved by a man; a female sweetheart," but the specific sense "a woman other than his wife with whom a man has a long-lasting sexual relationship," to quote the Oxford English Dictionary's definition, doesn't appear until the early 17th century. (John Donne made this meaning particularly clear in a sermon mentioning "women, whom the Kings were to take for their Wives, and not for Mistresses, (which is but a later name for Concubines).")

This bare dictionary definition, even with the emphasis on "long-lasting," doesn't fully capture the nuances of mistress's use. A mistress is exclusively devoted to one man. Although that man may have other partners, his relationship with his mistress is relatively serious and stable. He may even pay to support her, or at least help cover some of her living expenses. This signification comes across in characteristic quotations from such authors as Edith Wharton ("Is it your idea, then, that I should live with you as your mistress—since I can't be your wife?"), F. Scott Fitzgerald ("There is always a halt there of at least a minute, and it was because of this that I first met Tom Buchanan's mistress. The fact that he had one was insisted upon wherever he was known. His acquaintances resented the fact that he turned up in popular restaurants with her"), and John Updike ("He phoned the news, not to his wife, whom it would sadden, but to his mistress").

If the type of romantic partnership that mistress evokes seems a little quaint, that points to the very problem with the word in current use: It refers to a social role for women that is increasingly rare, because it is increasingly unnecessary, in modern-day America.

So, "mistress" would be the word Daniel Burke was looking for in this RNS piece last week about Thomas Merton's affair with a young student nurse. Their fling involved commitment and devotion, albeit only for the few months before Merton re-devoted himself to the monastic life.

So too would Steve McNair's lover-killer have been his mistress, though most media outlets labeled her as his "girlfriend."

Sheidlower touches on a principle recently proposed by the social critics Matt Stone and Trey Parker (AKA the creators of "South Park): A word's meaning can change overtime. But in the end he says that though he doesn't think mistress is a good fit, there really isn't anything better in the English language.

Girlfriend usually implies an ongoing relationship, as does lover, which is in any case regarded by many media outlets as a bit too explicit. There are also expressions, often slangy, for the relationship itself, including affair (which can, but does not always, imply a continuing relationship), one-night stand, or hookup. These expressions, however, or more circumlocutory descriptions ("a woman with whom Tiger Woods had an affair"), are clunky and therefore not appropriate for headlines.

In other words, they're mistresses.

You could argue that this is all just semantics. And it is. But words matter. And, far too often, journalists use language inaccurately.

Here, however, it seems they got it right. But if they are in need of an alternative, I'm a fan of using the old-fashioned and biblical "co-adulterers."