Source: Image of Pica comparison, by Maria Tucker Image of Dog comparison, by Maria Tucker Image of x-height, ascender, descender, baseline, mean line and x-height, Public Domain http://en.wikipedia.org/wiki/File:Typography_Line_Terms.svg Image of Old Style charcters and numerals, by Maria Tucker
The unit used when measuring the length of a line of type. There are 6 picas in an inch.
The unit used when measuring letterforms. A point measures 1/72 of an inch. Type is measured vertically from the bottom of the descender to the top of the ascender.
In a lower case letter, the vertical distance from the baseline to the mean line.
The name for the part of a typographic character that extends below the baseline or any character which has a descender.
The name for the part of a typographic character that extends above the mean line or any character which has an ascender.
In a lower case letter, an implied horizontal line which falls across the top of the letter x.
The implied horizontal line upon which typographic characters sit.