Diacritic
Diacritic , adjective
[Greek diakritiko`s, from diakri`nein to separate, distinguish; dia` through + kri`nw to separate. See Critic.]
That separates or distinguishes; -- applied to points or marks used to distinguish letters of similar form, or different sounds of the same letter, as, ā, a, a, ō, o, etc.
Diacritical points.
A glance at this typography will reveal great difficulties, which diacritical marks necessarily throw in the way of both printer and writer.
Also: Diacritical