There is a standard set of terms to describe the parts of a character. These terms, and the parts of the letter they represent, are often referred to as "letter anatomy" or "typeface anatomy." By breaking down letters into parts, a designer can better understand how type is created and altered and how to use it effectively.
In the images below, the part of the character being discussed is in red, or circled in red. A few extra terms, such as baseline and x-height, are included to help understand and describe the letter anatomy.
The baseline is the invisible line on which characters sit. While the baseline may differ from typeface to typeface, it is consistent within a typeface. Rounded letters such as "e" may extend slightly below the baseline.
The meanline falls at the top of many lowercase letters such as "e," "g" and "y." It is also at the curve of letters like "h."
The x-height is the distance between the meanline and the baseline. It is referred to as the x-height because it is the height of a lowercase "x." This height can vary greatly between typefaces.
The cap height is the distance from the baseline to the top of uppercase letters like "H" and "J."
The part of a character that extends above the meanline is known as an ascender. Note that this is the same as extending above the x-height.
The part of a character that extends below the baseline is known as a descender, such as the bottom stroke of a "y."
Fonts are often divided into serif and sans serif. Serif fonts are distinguishable by the extra stroke at the ends of the character, known as a serif.
The vertical line of a "B" and the primary diagonal line of a "V" are known as the stem. The stem is often the main "body" of a letter.
The horizontal lines of an "E" are known as bars. Bars are horizontal or diagonal lines of a letter, also known as arms, and are open on at least one side.
An open or closed circular line that creates an interior space, such as in "e" and "b."