The word lapel is used when referring to the fold of the front of the coat that is a continuation of the collar, and which usually is separated by a notch in the collar. Army reg.670-1 Branch Insignia-how worn, sec. 28.12 page 230.
Very cool collar disc. Here is the link I use to date them. I mean to find out what time period they are from, I don’t take them on dates, that would be weird.
Thanks Casper. Didn't see this one, but that gives me some idea of values. I have found a few of those Marine pins with the eagle on top of the world. Who would have known they sell for $100 ea.