Aperture Opening at the end of an open counter.

Arm A horizontal stroke not connected on one or both ends.

Ascender An upward vertical stroke found on lowercase letters that extends above the typeface’s x-height.

Baseline The invisible line where letters sit.

Bowl A curved stroke that encloses a letter’s counter.

Counter Fully or partially enclosed space within a letter.

Crossbar A horizontal stroke.

Descender A downward vertical stroke found on lowercase letters that extends below the baseline.

Diagonal Stroke An angled stroke.

Ear A small stroke projecting from the upper right bowl of some lowercase g’s.

Finial A tapered or curved end.

Hairline The thin strokes of a serif typeface.

Ligature Two or more letters are joined together to form one glyph.

Link A stroke that connects the top and bottom bowls of lowercase double-story g’s.

Loop The enclosed or partially enclosed counter below the baseline of a double-story g.

Lowercase The smaller form of letters in a typeface.

Serif “Feet” or non-structural details at the ends of some strokes.

Shoulder A curved stroke originating from a stem.

Small Caps Uppercase characters that appear as a smaller size than the capital height of a typeface. Short for “small capitals”.

Spine The main curved stroke for a capital and lowercase s.

Spur A small projection from a curved stroke.

Stem Primary vertical stroke.

Tail A descending stroke, often decorative.

Terminal The end of a stroke that lacks a serif.

Uppercase A letter or group of letters of the size and form generally used to begin sentences and proper nouns. Also known as “capital letters”.