what is any single mark that makes up part of a typographic symbol
Glyph In typography, a glyph /ɡlɪf/ is an elemental symbol within an agreed set of symbols, intended to represent a readable character for the purposes of writing. Glyphs are considered to be unique marks that collectively add up to the spelling of a word or contribute to a specific meaning of what is written, with that meaning dependent on cultural and social usage. In contrast, in most languages written in any variety of the Latin alphabet, the dot on a lower-case i is not a glyph because it does not convey any distinction, and an i in which the dot has been accidentally omitted is still likely to be recognized correctly. However, in Turkish it is a glyph because that language has two distinct versions of the letter i, with and without a dot. Also, in Japanese syllabaries, a number of the characters are made up of more than one separate mark, but in general these separate marks are not glyphs because they have no meaning by themselves. However, in some cases, additional marks fulfill the role of diacritics, to differentiate distinct characters. Such additional marks constitute glyphs. In general, a diacritic is a glyph, even if it is contiguous with the rest of the character like a cedilla in French, the ogonek in several languages, or the stroke on a Polish "Ł".
No symbol The international prohibition sign (official name), (also known as a no symbol, no sign, circle-backslash symbol, nay, interdictory circle, or universal no) is a red circle with a red diagonal line through it (running from top left to bottom right), completely enclosing a pictogram to indicate something is not permitted. The prohibition sign is sometimes seen in all-black, where color is not available.