legible

Legible describes text that can be easily recognized and read. In typography, legibility refers to the ease with which individual characters can be distinguished and the text can be read at a glance. The term is also used for handwriting, signage, and digital displays. The word derives from the Latin legibilis, meaning readable.

Several factors influence legibility. Typeface design affects character distinctness: letter shapes, x-height, stroke contrast, and the differentiation of similar characters such as I, l, 1 or O, 0. Size, weight, and spacing (tracking and kerning) determine how tightly text can be perceived. Leading, line length, and line breaks influence the flow of reading. Color and contrast between text and background, as well as lighting and display resolution, also matter, especially on screens or at a distance.

Legibility is distinct from readability. Legibility concerns recognizing letters and words; readability concerns comprehension and processing of meaning. Accessibility considerations aim to maximize legibility for diverse readers, including those with vision impairment or aging eyes, through higher contrast, scalable type, and clear, unambiguous character shapes.

Practical guidance emphasizes choosing legible typefaces, favoring clear letterforms and sufficient spacing, avoiding highly similar characters, ensuring adequate size and contrast, and testing under real-world conditions. For signage, sans-serif designs with wide apertures are common; for body text on screens, responsive typography with readable sizes across devices is preferred. Compliance frameworks such as WCAG advocate sufficient color contrast and legible text presentation.