What is a glyph

I also intend to post properties and qualities of good fonts... but first i think some things need to be cleared...

WHAT IS A GLYPH?

• A glyph is a fancy word for a shape. It is a component that makes up an outline font. For example, the dot on the letter "i" is a glyph, as is the vertical line, as are the serifs. Glyphs determine the shape of the font.
  

• The actual shape (bit pattern, outline) of a character image. For example, an italic "A" and a roman "A" are two different glyphs representing the same underlying character. Strictly speaking, any two images that differ in shape constitute different glyphs. ...

• Every character in a typeface, (eg: G, $, ?, and 7), is represented by a glyph. A typeface may contain more than one glyph for each character. These are usually referred to as alternates.
  

• A displayable character.
  

also check out wikipedia http://en.wikipedia.org/wiki/Glyph