The word marriage has been the subject of a huge amount of political and legal wrangling, and dictionaries have lately been caught in the crossfire. With major English dictionaries expanding their definitions of marriage to encompass same-sex unions, lexicographers have taken hits from liberals and conservatives alike. Those opposed to same-sex marriage would prefer that dictionaries maintain the traditional definition, while those on the other side of the debate argue that same-sex marriage shouldn't be treated as secondary. Lexicographers find themselves in a no-win situation.

As I describe in my most recent column for the Boston Globe, English-language dictionaries have been modifying their definitions of marriage over the past decade, as same-sex marriage has received greater cultural recognition and legal standing in various jurisdictions. The 11th edition of Merriam-Webster's Collegiate Dictionary, first published in 2003, revised its primary definition to read:

(1) : the state of being united to a person of the opposite sex as husband or wife in a consensual and contractual relationship recognized by law
(2) : the state of being united to a person of the same sex in a relationship like that of a traditional marriage <same-sex marriage>

Similarly, the Random House entry (currently licensed by Dictionary.com) was changed to read:

a. the social institution under which a man and woman establish their decision to live as husband and wife by legal commitments, religious ceremonies, etc.
b. a similar institution involving partners of the same gender: gay marriage.

The latest dictionaries from American Heritage and Oxford explicitly point to the changing legal scene, both saying that marriage can apply to same-sex couples "in some jurisdictions." All of these dictionaries are somewhat hampered by the necessity of providing a terse, compact definition to a complex cultural, legal, and religious institution. At Vocabulary.com (the sister site of the Visual Thesaurus), the explanation given for the word marriage is more discursive, allowing for a better handle on the term's current nuances.

Though the different dictionary publishers have taken slightly varying approaches, they all have found room for the expanded sense of marriage, reflecting usage even among those who disagree with the legal advances of same-sex marriage in the United States and elsewhere. (Currently, six states in the U.S. recognize same-sex marriage, and ten countries recognize it nationwide.) As I say in the Globe column, even someone like Rick Santorum uses this newer sense of marriage as he argues against it. But I note that it's possible that Santorum sees same-sex marriage as a compound like peanut butter or jellyfish, where "X Y" isn't actually a kind of "Y." (Think also of poor Pluto, which is now classified as a dwarf planet but not a planet.) The Stanford linguist Arnold Zwicky calls these compounds "resembloid composites" — because, for instance, a jellyfish only resembles a fish without technically falling into the fish category.

While those opposed to same-sex marriage take issue with this extension of marriage, those now currently complaining about the Random House/Dictionary.com entry (in the form of a Change.org petition with more than 100,000 signatures) would like to replace the two-part definition with a single, gender-neutral version. But same-sex marriage is still what linguists would call a "marked category": marriage between a man and a woman is the "unmarked" cultural default, with same-sex marriage a semantic extension from the default. There may come a time when this "markedness" relationship disappears (leaving "heterosexual marriage" as a kind of retronym like analog clock or acoustic guitar), but in the meantime, lexicographers are likely to continue treating same-sex marriage as a subsidiary sense — not to disparage it, but to show how it is a later elaboration on the primary meaning.

For more discussion of this tricky terrain, check out my interview on NPR's "Talk of the Nation" with Neal Conan.