Er sorry no, you're all wrong except for Willow who was being too subtitle
16 is the collar size in inches, 41 is the collar size in cm. They both refer to the collar. Most off-the-peg men's formal shirts in the UK are sold by collar size. Nothing mystical about it! Casual shirts tend to be sold in Small (S), Medium (M), Large (L), or Extra Large (XL).
The best thing to do is try them on before you part with your cash to make sure it fits.
If you're going to a tailor rather than buying off-the-peg, the tailor will take all the measurements he needs, so don't worry about that. He will know how much fabric you require to make your shirt and tux.
[ 04-26-2003, 09:15 AM: Message edited by: Epona ]