The Royal Wedding invitations have been sent out and they note proper dress attire is "Uniform, Morning Coat or Lounge Suit."
What is a lounge suit, anyway?
Dictionary.com defines lounge suit as, "a man's suit appropriate for informal occasions," and classifies it as Chiefly British.
According to Encyclopedia Britannica, it first appeared in the mid-1800s and it is "informal wear" traditionally (but not always) consisting of trousers, a waistcoast or vest and a short coat.
An Economist article notes that the lounge suit is best known for its rise in American business culture at the end of the 19th century. It is often referred to as the most common style of Western suit today.
Some 1,900 guests have been invited to the Royal Wedding. See the official invitation here.
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