S

Sans-serif

Type-styles that lacks the serif stroke at the end of the horizontal or vertical strokes of the main letter-form.

Serif

A serif font is a typeface that has an extra stroke at the end of the vertical and horizontal strokes of the main letter-form. A font that doesn't have this extra stroke is known as sans-serif.
 
Examples of serif typefaces include Times, Garamond, Goudy and Palatino. It used to be a commonly accepted wisdom that serif fonts were more readable than sans-serf for large blocks of printed body copy. This theory has been questioned in recent times - but the argument still rages amongst designers.

See also: Serif Vs Sans-serif

Stem

The vertical stokes that make up the main part of most characters containing straight lines - the letter 'O' does not contain a stem.

Small caps

Literally, Small Capitals. Typeface style where all the letterforms take the shape of its capital letter. However, the lowercase letters are smaller than the uppercase and generally, but not always, align with the same x-height as the regular Roman face, for the same font family.

Spine

The curved centre of the stroke of the letter 'S'.

Spur

The finishing serif at the ends of an 'S' or 'C' character.

Stem

The vertical stokes that make up the main part of most characters containing straight lines - the letter 'O' does not contain a stem.

Subscript

Character which appears lower and much smaller than the main line of text. Often used for chemical symbols.

Superscript

Much smaller character than the line it appears on and appears above the y-height.

Swash

Decorative letterforms, generally used for headings os as initial caps.

Symbol font

Special typeface used for scientific or mathematical formulas.