I was watching the British show New Tricks (the "London Underground" episode), and heard the character DCI Sasha Miller tell another detective that he's someone's "secondment." I had to look up the meaning, since I've never seen or heard it, especially in any kind of media or fictional story. Even when I type the word in this post, it gets underlined in the draft as if it's a spelling mistake (underlined to be spell-checked). My American Heritage Dictionary book doesn't include it, and it's not on their website, either. I even have a large Webster's Encyclopedic Unabridged Dictionary of the English Language, and it's nowhere to be found.

So I'm concluding it's a British word, and that's what the Oxford dictionary says, too. The way the word was used in the show, I assumed it was alluding to the more "traditional" meaning of the word, which is found at the Merriam-Webster site: "the detachment of a person (such as a military officer) from his or her regular organization for temporary assignment elsewhere." But Oxford defines it as "The temporary transfer of an official or worker to another position or employment." I'm guessing that the Oxford definition (which also shows up elsewhere online) is the contemporary meaning of the word, which is probably a result of the evolution from military to civilian use because work takes up so much of our lives. Basically, when Sasha was telling the other detective to work with someone else on an aspect of the case, the meaning could fall in either camp.

The word seems to be major enough in England to cause people to write on websites about it. For instance, one article on a job site gives advice about "Going on secondment". I bet such advice has never existed on American sites; if people were to see such an article, they'd wonder what it actually means. It seems like a foreign word, even though we share the same language. And Brits reading this would probably think I'm making too much of it. But it's new to me, and another word that shows how our English languages can be dialectical in some respects :p

The full episode is below (which is very kind of the show's producers to post online).