Apex: the head of a pointed letter.
Arm: a horizontal or diagonal stroke extending from a stem.
Ascender: the part of lowercase letters, b, d, f, h, k, l, and t that rise above the x-height.
Baseline: defines the bottom of capital letters and of lowercase letters.
Bowl: a curved stroke that encloses a counter.
Capline: defines the height of capital letters.
Character: a letter form, number, punctuation, mark or any single unit in a font.
Counter: fully or partially enclosed negative spaces created by the stokes of a letter.
Crossbar: the horizontal stroke connecting two sides of a letterform, as in an “A”.
Descender: the part of a lowercase letters, g, j, p, q, and y that falls below the baseline.
Descender line: Defines the depth of lowercase descenders.
Foot: the bottom portion of a letter.
Hairline: the thin stroke of a Roman letter.
Head: the top portion of a letter
Ligature: two or more letters linked together.
Lowercase: the smaller set of letters, a name derived from the days of metal typesetting when these letters were stored in the lower case.
Serifs: ending strokes of characters.
Stem: the main upright stroke of a letter.
Stroke: a straight or curved like forming a letter.
Terminal: the end of a stroke not terminated with a serif.
Uppercase: the larger set of letters or capitals.
Vertex: the foot of a pointed letter.
x-height: the height of a lowercase letter excluding ascenders and descenders.

Egyptian: a style of Roman letter characterized by heavy, slab-like serifs. Thin strokes are usually fairly heavy. Also called square serif or slab serif.
Italic: letterform design resembling handwriting. Letters slant to the right and are unjoined. Originally used as an independent design alternative to Roman. Now used as a style variant of a typeface within a type family.
Modern: a style of Roman letter whose form is determined by mechanical drawing tool rather than the chisel-edge pen. Characterized by extreme thick and thin contrast, vertical-horizontal stress and straight, unbracketed serifs.
Old Style: a style of Roman letter, most directly descended in form from chisel-edge drawn models, retaining many of these design characteristics. Characterized by angled and bracketed serifs, biased stress, and less thick-thin contrast.
Sans Serif: letterform design with out serifs and usually having monoline stroke weights (no clearly discernible thick and thin variations.)
Script: letterform design most resembling handwriting. Letters usually slant to the right and are joined. Script types can emulate forms written with chisel-edge pen, flexible pen, pencil, or brush.
Serifs: There are many different types of serifs, for example, bracketed, hairline, oblique, pointed, round, square, straight, and unbracketed.
Stress: the stress of letterforms is the axis created by the thick/thin contrast; stress can be left-slanted, right-slanted, or vertical.
Thick/thin contrast or strokes: the thickness of the strokes caries in typefaces, that is, the amount of weight differs between thick and thin strokes.
Transitional: a style of Roman letter that exhibits design characteristics of both Modern and Old Syle faces.
Weight: the thickness of the strokes of a letterform, determined by comparing the thickness of the strokes in relation to the height, for example light, medium, and bold.