Deployment is commonly used in the military to describe shipping out overseas. The correct word for that clasp is d-e-p-l-o-y-a-n-t, the Americanized spelling of the French word. French is a language spoken in Switzerland, the capital of the watchmaking world. As a matter of fact, some of Switzerland where watches are made was originally French territory that was lost after Napoleon's defeat.
There are plenty of French words used in America every day. Voila, carte blanche, petite, a la carte, sans, blonde, brunette, cuisine, rouge, avante grade, chic, encore, matinee, gauche......
The correct term is deployant clasp - scroll down:
http://www.chronocentric.com/watches/terms.shtml
Here's some more fun for you:
http://forums.watchuseek.com/f2/time-settle-once-all-deployant-vs-deployment-360266.html
Deployant roughly translates to "folding". Type "folding clasp" into Google translate (English to French) and you get "boucle déployante".
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