A squared building stone finely dressed on all sides adjacent to those of other stones so as to permit very thin mortar joints

Ashlar brick (rock-faced brick): A brick whose face has been hacked to resemble roughly hacked stone

Ashlar masonry: Smooth square or rectangular stones laid with mortar in horizontal courses

Coursed ashlar: Ashlar masonry built of stones having the same height within each course, but each course varying in height

Random Ashlar: Ashlar masonry where stones appear to be laid without a drawn pattern, although the pattern may be repeated

Information provided by: http://ah.bfn.org