The definition of marriage is the hottest topic in US news lately.
My favorite place for looking up definitions of English words is, unsurprisingly, the Merriam-Webster dictionary.
And indeed, the editors of M-W’s website noticed the public interest in the definition of marriage, and here’s what they had to write about it:
The word became the subject of renewed scrutiny as the Supreme Court heard arguments in cases seeking to overturn California’s ban on gay marriage and the federal government’s Defense of Marriage Act.
Marriage has become a controversial definition, although its original sense – “the state of being united to a person of the opposite sex” – has not changed.
However, because the word is used in phrases such as “same-sex marriage” and “gay marriage” (by proponents and opponents alike), a second definition – “the state of being united to a person of the same sex in a relationship like that of a traditional marriage” – was added to the dictionary to provide an accurate picture of the word’s current use.
I recently read Herbert Morton’s excellent book The Story of Webster’s Third: Philip Gove’s Controversial Dictionary and Its Critics. It’s excellent because it’s very well written and because it could be a handbook in how to make dictionaries in general: how to balance scientific linguistic precision with usefulness to the general public.
Sadly, this remark about the definition of marriage is a departure from the principles of excellence that guided the editors of Webster’s Third. If the sentence says “same-sex marriage”, then “same-sex” means, literally, “same-sex”; there’s no need to say “the state of being united to a person of the same sex“.
Why not just say that “marriage” is “the state of being united to a person”? Maybe “legally united”, or “religiously united”. Or “united in a family”. It neatly avoids the political problems around sex and gender and all that, and is correct linguistically.
The official dictionary of the Catalan language already did it:

The Institute of Catalan Studies, which publishes the dictionary, also publishes a list of updates in each edition. In this image you can see how the definition of marriage changed from “a legal union of a man and a woman” to “a legitimate union of two people who promise each other a common life, established through certain rituals or legal formalities”. The last usage example also says: “In some countries the legislation provides for marriage between two persons of the same sex”.
And well, yes, before you ask: of course there is a political background. Catalonia was one of the first jurisdictions that made same-sex marriage equal to different-sex marriage. But from the purely linguistic point of view the newer definition, which doesn’t mention a man and a woman, is perfectly correct. And saying that the definition of “marriage” is different in “marriage” and in “same-sex marriage” is not correct. Simple, really.