typDef.

Absolute Measurement- measurements that are expressed in finite units such as centimeters, inches or picas.
Relative Measurement- measurements that are not expressed in an actual size. Type that is measured by point (which is concerned only with the height of a character) would be considered a relative measurement.
Point- a unit of measurement used to gage the height of a fonts type block.
Pica- a font that was most commonly used on typewriters, designed to fit ten characters to an inch.
Em (and em dash)- a unit of measurement used determine spacing functions; 1 em is equal to the number of points that are being used to represent the current font. An em dash is a punctuation mark commonly used to express a lull in dialogue. It is the length of one em.
En (and en dash)- a unit of measurement that is half the size of one em. Consequently the en dash is half the size of an em dash.
Legibility- the extent to which a typeface can be read.
Rag- the ragged edge of a block of text.
Flush left- type is aligned to the left with the left side of the page.
Flush right- type is aligned with the right side of the page.
Centered- type is positioned in the center of the left and right margins and is not flush with either.
Justified- characters are spaced so that the type is aligned to both the right and left of the margins
advantages/disadvantages- can make text more accessible to the reader or more visually appealing. However, it can also do the opposite.
Word spacing (ideal)- as the character increases in size, so should the word spacing.
Rivers- a vertical white space that occurs when spaces between words line up.
Indent- the space at the beginning of a paragraph. Used to make the layout more accessible to the reader.
Leading-the direction the viewers eye was intended to be guided.
Kerning- when the space between tow letters is modified to something other than what is normal.
Tracking- the adjustment of space between all letters in general.
Weight- the thickness of a typeface (bold).
Scale- the point size of a font.
Typographic variation- the variation of how type is used by typographers.
Orphan- a small amount of lines that are pushed beyond the margins, creating a new column.
Widow- a last line of a paragraph that consists of only a few words.