Does a Flag Fly at Half-Staff or Half-Mast?

While I've primarily heard "flying a flag at half-staff," I wasn't certain of the reasons for using either term with the American flag. So I put a little research time into this. One of the first things I found was a good article dealing with this exact question from a Canadian perspective. The US Flag Code TITLE 4 > CHAPTER 1 > Sec. 7. "Position and manner of display" consistently uses the phrase "half-staff" throughout subsection (m) including "(m)(1) the term ''half-staff'' means the position of the flag when it is one-half the distance between the top and bottom of the staff;" A Google search of the whitehouse.gov website shows consistent use of the phrase "Half-staff" and no use of "half-mast" There is one example in a recent White House press release related to an Executive Order on when to fly the flag at half-staff. On the other hand, both dictionary.com and Merriam-Webster online defer any definition of "half-staff" & instead list "see half-mast." Definitions for half-mast ...  more