What does undercutting refer to?

I have been checking e-bay for a decent flute I can afford, I have seen several that say the embrochure and/or finger holes are “undercut”. Can someone explain this to me?
Thanks

Ron,

Undercutting is generally a good thing.

Check the following web pages (flute factory tour 2 & 3 ) for a graphic explanation.

http://www.yamaha.co.jp/edu/english/factory/fl/fl_002.html

Bill