Originally Posted by bluemagic
Your friend is probably an ignoramus who calls it a "button collar."
Bad idea to get into a nomenclature barney on this. In England these are always called 'button down' shirts as the collar is buttoned down.
But in America non dress shirts have become so ubiquitous that 'button down' often is used to denote any dress shirt with buttons down the front, hence the advent of the term 'button collar' to denote this particular style.